In a large mixing bowl, combine the chickpeas, black beans, kidney beans, cherry tomatoes, cucumber, red onion, and parsley.
In a separate small bowl, whisk together the olive oil, red wine vinegar, garlic powder, dried oregano, salt, and pepper until well combined.
Pour the dressing over the bean and vegetable mixture. Toss gently to coat all ingredients evenly.
Cover the salad and refrigerate for at least 30 minutes to allow the flavors to meld.
Before serving, give the salad a gentle toss and adjust seasoning if necessary.