In a large bowl, combine the tomatoes, cucumber, red onion, and olives.
In a small bowl, whisk together the olive oil, red wine vinegar, oregano, salt, and black pepper.
Pour the dressing over the vegetables and toss gently to coat.
Arrange the feta slices on top or crumble over the salad.
Let the salad sit for about 10 minutes before serving to allow the flavors to blend.
Serve at room temperature and enjoy the bright, fresh flavors that feel like spring finally trying to arrive.