Method
In a large mixing bowl, gently combine the rinsed black beans, thawed corn, chopped red bell pepper, and chopped red onion.
In a small bowl or liquid measuring cup, whisk together the lime juice, olive oil, cumin, salt, and black pepper until the dressing is well combined.
Pour the dressing over the bean and vegetable mixture and stir gently with a large spoon until all ingredients are evenly coated.
Gently fold in the chopped cilantro and diced avocado, being careful not to mash the avocado, to maintain its texture.
For the best flavor, cover the bowl and let the salad rest in the refrigerator for at least 15 minutes before serving to allow the flavors to meld.