To cut the tomatoes, quarter and then cut each quarter into 2 to 3 pieces depending on the tomato's size. You are looking for 1 inch pieces of tomato.
Cut the cucumbers into chunks of similar size to the tomatoes.
Slice the red onion lengthwise into thin slices. Soak in ice water with a squeeze of lemon for 5 minutes to remove some of the bite. Drain and set aside.
Slice or break the feta into small chunks just under 1 inch cubed, or a little smaller than the cucumber and tomato pieces.
For the dressing mix the olive oil, red wine vinegar, dried oregano, salt and pepper in a small bowl stirring to combine. The dressing will not emulsify fully but that is okay.
To assemble the salad, combine the tomato, cucumber, onions, and kalamata olives in a serving bowl or platter. Sprinkle with salt and pour over the dressing and toss to coat. Let the salad rest for 5-10 minutes to let the vegetables soak up some of the dressing before topping with the feta pieces. Finish with a light drizzle of olive oil and a sprinkle of salt and if you desire a squeeze of lemon or a sprinkling of capers (if using).