Wash and chop the vegetables: Dice the English cucumber, slice the Roma tomatoes, and finely chop the red onion.

Pit and halve the Kalamata olives, and add them to the vegetable mixture. Crumble feta cheese into the bowl.

Whisk together olive oil, red wine vinegar, Greek oregano, kosher salt, and freshly ground black pepper in a small bowl.

Drizzle the dressing over the salad mixture and toss gently using a spatula.

Serve immediately or chill for a few minutes before serving.