Prep the produce: Slice the cucumbers thinly. Chop or halve the tomatoes.
Thinly slice the red onion. Add everything to a large bowl.
Make the marinade: In a small bowl, whisk olive oil, vinegar, lemon juice, honey, garlic, oregano, salt, and pepper until emulsified.
Toss and taste: Pour the dressing over the vegetables. Add the chopped dill or parsley.
Toss gently to coat. Taste and adjust salt, pepper, or acidity.
Marinate: Cover and refrigerate for at least 20–30 minutes, or up to 4 hours, to let the flavors meld. Stir once midway if you can.
Finish and serve: Just before serving, taste again.
Add feta, olives, or a pinch of red pepper flakes if using. Serve chilled or at cool room temperature.