Start by gathering your ingredients. Drain and rinse the black, kidney, and cannellini beans in a colander until the water runs clear. Then, chop the green and red bell peppers and the red onion into small, uniform pieces for even flavor.

In a large mixing bowl, combine the drained and rinsed beans, chopped bell peppers, thawed corn, and red onion. Use a large spoon or spatula to mix everything until well integrated.

In a separate bowl, whisk together the olive oil, red wine vinegar, fresh lime juice, and lemon juice until emulsified. Add minced garlic, white sugar, salt, ground cumin, black pepper, chili powder, and chopped fresh cilantro. Adjust seasonings to your taste.

Pour the dressing over the salad mixture in the large bowl. Toss gently until everything is evenly coated with the zesty dressing.

Cover the bowl with plastic wrap or a lid and refrigerate the Mexican Bean Salad for about 1 hour to allow the flavors to deepen.

Before serving, give the salad a final toss. Enjoy chilled as a side dish or with tortilla chips as a hearty dip.