Thinly slice the red onion and place the slices into a bowl of ice water.
Combine olive oil, vinegar (if using), 1.5 teaspoon oregano, salt and pepper in a large shallow bowl. Stir with a spoon.
Cut the tomatoes into wedges (if using large tomatoes) or in half (if using cherry or grape tomatoes). Add to the bowl with dressing. (If the stems of your tomatoes are hard, remove them.)
Cut the cucumbers in half, and then slice thin half-moon shapes. Add the slices to the bowl with the dressing.
Drain the onions well and add them to the bowl with the vegetables and dressing.
Pit the olives. If you don't have an olive pitter, use the flat side of a knife to gently flatten each olive. Then remove the pit where the olive has split. Discard the pits.
Add the pitted olives to the salad.
Place the feta on top of the salad, and sprinkle everything with the remaining .5 teaspoon of dried oregano. Add a drizzle of olive oil over the salad.
When serving, break the cheese into several pieces so everyone can get some feta on their plates.
Video
Notes
Always wash your produce before you slice or chop it.
Soak sliced red onion in ice water for 15 – 20 minutes to soften its bite while keeping it crisp.
I used a small amount of red onions. You can use more if you wish.
Substitute red onions with shallots if needed.
Leave tomato pulp and seeds in place; their juices mingle with the oil and herbs to become the dressing.
For Campari-sized tomatoes (a.k.a. cocktail tomatoes), I cut each tomato into eighths. You want the piece to be small enough to fit onto a fork.
If your chef’s knife struggles with tomato skins, use a serrated blade for clean cuts.
Gently press each Kalamata olive with the flat side of a knife (or use an olive pitter) to pop out the pit.
Using winter tomatoes? Make sure to add the vinegar to brighten the salad.
Feta blocks are sold in various sizes. I prefer a 7 oz (200 g) block, but a 5 oz (150 g) block will also work.
Substitutions
Olives: black or green olives also work, though the flavour will differ.
Feta: swap in a good vegan feta for a dairy-free version.
Vinegar (optional): use red wine vinegar if you don't have white wine vinegar.
Oregano: If you use fresh oregano, you may want to use more than 2 teaspoon finely chopped.
Make-ahead & StoragePrep the vegetables and dressing up to a day ahead, but keep them separate. Combine just before serving so everything stays crisp.Store leftovers covered in the fridge for up to 2 days, but note that textures will become soggier over time.