In a mixing bowl, combine the diced cucumber, crumbled feta cheese, halved cherry tomatoes, chopped red onion, and parsley.

In a separate small bowl, whisk together the olive oil, red wine vinegar, dijon mustard, minced garlic, salt, and pepper.

Pour the dressing over the salad and toss gently to combine.

Serve immediately or refrigerate for 30 minutes to allow flavors to meld.