In a large mixing bowl, combine the cannellini beans, chickpeas, sun-dried tomatoes, 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 mixture and gently toss until everything is evenly coated.
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.