Drain and rinse the kidney beans, chickpeas, and green beans thoroughly.

Dice the red onion and bell pepper into small pieces.

In a large mixing bowl, combine the beans and diced vegetables. Stir gently.

In a separate bowl, whisk together olive oil, red wine vinegar, garlic powder, salt, and pepper.

Pour the dressing over the bean mixture and mix until everything is coated.

Cover the salad and let it chill in the refrigerator for at least 30 minutes.

Before serving, sprinkle fresh parsley on top.

Serve chilled or at room temperature.