In a mixing bowl, combine corn, diced tomatoes, red onion, cilantro, lime juice, salt, and black pepper. Mix well and set aside.

In a bowl, mash the avocados. Stir in diced tomato, onion, lime juice, salt, and jalapeño (if using). Mix until combined.

In a pot, heat olive oil over medium heat. Add minced garlic and sauté until fragrant. Add black beans, cumin, and salt. Mash the beans with a fork or potato masher, adding water as needed to reach desired consistency.