01 - Place kidney beans, red onion, red bell pepper, cucumber, cherry tomatoes, and parsley in a large mixing bowl and toss to distribute evenly.
02 - Whisk together olive oil, red wine vinegar, Dijon mustard, garlic, salt, and black pepper in a small bowl until fully emulsified and smooth.
03 - Pour the vinaigrette over the vegetable and bean mixture. Gently toss until all ingredients are lightly coated.
04 - Taste and adjust seasoning if needed. Refrigerate for at least 30 minutes to allow flavors to meld before serving.