Steps
1. Slice the cucumber into thin rounds and quarter the tomato.
2. Thinly slice the red onion.
3. In a small bowl, whisk together the olive oil, red wine vinegar, Dijon mustard, salt, and pepper to make the vinaigrette.
4. In a salad bowl, combine the cucumber, tomato, and red onion.
5. Drizzle the vinaigrette over the vegetables and toss gently to coat.
6. Let the salad marinate in the fridge for at least 15 minutes before serving.
7. Serve chilled and enjoy!