Prepare the Vegetables. Chop cucumbers and thinly slice the red onion.
Mix the Dressing. In a small bowl, whisk together olive oil, lemon juice, minced garlic, oregano, salt, and pepper.
Combine and Toss. In a large mixing bowl, combine all vegetables, olives, and crumbled feta. Pour the dressing over the salad and toss gently to combine.
Chill and Serve. Let the salad sit for a few minutes to marinate or serve immediately, garnished with extra herbs or feta if desired.