Combine the cucumbers, bell peppers, garbanzo beans, cannellini beans, red onion, Kalamata olives, banana peppers, and pepperoncinis in a bowl.
In a separate bowl, whisk together the balsamic vinegar, white wine vinegar, Dijon mustard, banana pepper juice, pepperoncini juice, lemon juice, dried herbs, salt, and pepper.
Pour the dressing over the bean salad and toss to coat.
