In a large mixing bowl, combine the black beans, corn, cherry tomatoes, and red onion.
In a separate small bowl, whisk together the olive oil, lime juice, ground cumin, salt, and black pepper until fully emulsified.
Pour the dressing over the bean mixture and toss gently to ensure even distribution.
Carefully fold in the diced avocado and chopped cilantro, taking care to maintain the structure of the avocado pieces.
Serve immediately at room temperature or refrigerate for 30 minutes to allow flavors to meld.