Got fresh tomatoes? This cucumber tomato onion salad brings out the beauty of ripe tomatoes in a way you’ll want to eat again and again.

What’s better than the sweet, juicy taste of a ripe tomato? We get giddy the moment they start to appear in their crimson, golden, and neon green splendor. Fresh tomatoes are at their best in simple preparations. This tomato cucumber salad with red onion is just that: pure ingredients that when marinaded bring together the richest of flavors. This salad is perfect as a side dish for meals on the patio or summer barbecues: it goes with anything and everything. And the flavor is like pure gold.

Love tomato salads? Try Fresh Tomato Salad, Cucumber, Tomato & Avocado Salad, and Tomato, Basil & Mozzarella Salad.

Use only best quality, ripe tomatoes!

For the very best cucumber tomato onion salad, promise us one thing. Only make this salad with ripe summer tomatoes! Do not try to make this in the off-season, when grocery store tomatoes are pink and mealy. This will only result in a truly terrible cucumber tomato onion salad. As with all simple preparations, the flavor of this salad depends on the quality of its ingredients. Do not skimp on the tomatoes!

Farmers market tomatoes or garden grown are best. We recommend buying your tomatoes at a farmers market if you have access to one, or growing them yourself.
Store bought can work, too. Try to find the best looking heirloom tomatoes you can buy at your local grocery store. Hydroponic greenhouse tomatoes tend to have better flavors.
Find multi-colored for a vibrant look. Multi-colored tomatoes work well here: the more the colors, the more vibrant the salad!

How to make cucumber tomato onion salad

Combine juicy tomatoes with cool cucumber and zesty onion, and this tomato cucumber salad is like plant-based take on a Greek salad, without the standard feta cheese! Here’s how to make this it (or jump to the recipe below):

Soak the onion: Thinly slice the onion and let it soak for a few minutes in cold water. This helps to remove the strong bite of the onion.
Cut the veggies: Meanwhile, cut the cucumber into half-moons and the tomato into wedges. Finely chop the herbs.
Marinade: Combine all the veggies and herbs with olive oil, red wine vinegar and kosher salt. Allow it to marinade for at least 30 minutes, then serve.

Can I skip the marinading time?

Alex and I are always looking for shortcuts. This cucumber tomato onion salad calls for marinading for 30 minutes. Is it really necessary? Actually, yes! Here’s why:

The time lets the flavors meld and develop. We sampled this salad before and after the marinading time, and you’ll definitely notice a difference. Marinading allows the flavors to meld, and they’re much more developed than when the salad is freshly mixed together. So make sure to make this salad in advance, and let it do its magic while you’re getting together the rest of the meal.
Make ahead tip: If you’d like, you can make this salad up to 2 hours in advance and store it covered at room temperature until serving. We recommend to not refrigerate this salad: it dulls the flavors.

What are heirloom tomatoes?

What are heirloom tomatoes? Heirloom tomatoes are tomato varieties that have been passed down through generations by saving the seeds. When you buy heirloom tomatoes, you’ll notice that their color and shape are much more varied than the typical round red tomato. They can vary from chartreuse to gold to purple to orange, and from small to medium to large.

Do you have to use heirloom tomatoes in this recipe? Not at all. We just love the look that heirloom tomatoes give, with all their vibrant colors. They also typically have a variety and nuance in flavor that makes the overall salad more intriguing. But you can use any ripe tomato that you like.

How to grow herbs

For this cucumber tomato onion salad, we’ve used a mix of herbs: basil, thyme and oregano from our garden. We highly recommend growing herbs at home in the summer months: it only requires some pots and a sunny ledge! You don’t even need garden space. If you’re looking to grow herbs, here are some resources that we’ve put together:

The complexity that using a few different herbs brings a nuance to this salad. But if you don’t have herbs readily on hand, there’s no need to buy all three! Use basil if you can only use one, or if you can find both use basil and oregano.

How to serve it

How would you serve this cucumber tomato onion salad? We can think of so many summery recipes to accessorize with this salad; it’s perfect for a summer party, barbecue, or cookout on the deck. Here’s a few things we might serve with it:

Seafood: Broiled Salmon, Grilled Shrimp
Veggie Mains: Grilled Veggie Burger, Greek Veggie Skewers
Veggie Sides: Elote (or Oven Roasted Corn), Watermelon Salad, Grilled Caesar Salad, Greek Orzo Salad
Drinks: Peach Sangria, Virgin Piña Colada, Easy Frozen Sangria, Gin & Watermelon Cocktail
Desserts: Blueberry Cake, Peach Crisp with Basil, Frozen Hot Chocolate

This cucumber tomato onion salad recipe is…

Vegetarian, gluten-free, vegan, plant-based, and dairy-free.