Steps
1. In a medium bowl, combine the chopped tomato, sliced cucumber, Kalamata olives, and red onion.
2. In a small bowl, whisk together olive oil, red wine vinegar, dried oregano, salt, and pepper to make the vinaigrette.
3. Pour the vinaigrette over the salad ingredients and toss gently to combine.
4. Sprinkle the crumbled feta cheese on top.
5. Serve immediately or chill for 10 minutes to let flavors meld.