Steps
1. Slice the cucumber, tomato, and red onion into thin rounds.
2. In a bowl, combine the sliced vegetables.
3. Crumble the feta cheese over the vegetables.
4. In a separate small bowl, whisk together the olive oil, red wine vinegar, salt, and pepper.
5. Pour the dressing over the salad and toss gently to combine.
6. Serve immediately or refrigerate until ready to serve.