01 - Place kidney beans, red onion, red bell pepper, cucumber, cherry tomatoes, and parsley in a large mixing bowl.
02 - Whisk together olive oil, red wine vinegar, Dijon mustard, garlic, salt, and black pepper in a small bowl until fully emulsified.
03 - Pour dressing over vegetable and bean mixture. Toss gently to coat all ingredients evenly.
04 - Season to taste with additional salt and pepper if needed. Refrigerate for at least 30 minutes before serving to allow flavors to meld.