Rinse and drain all canned beans. Halve the cherry tomatoes, dice the cucumber, and finely chop the red onion.

In a large mixing bowl, combine the black beans, kidney beans, chickpeas, cherry tomatoes, cucumber, and red onion.

In a small bowl, whisk together the olive oil, red wine vinegar, minced garlic, salt, black pepper, and dried oregano.

Pour the dressing over the salad and toss gently to combine. Serve immediately or chill in the refrigerator for 30 minutes before serving.