Place the beans in a colander, rinse with cold water until the water runs clear, and pick out any discolored/dark beans. Transfer the beans to a large, lidded pot and cover with cold water by at least 2 inches.
Add 2 tablespoons minced fresh cilantro, 1 teaspoon cumin, ½ of the minced onion, 2 cloves minced garlic, 3 teaspoons kosher salt and ¼ teaspoon black pepper. Cover and bring to a boil over medium-high heat.
Once the beans are at a full boil, reduce the heat to low and simmer 1½-2 hours, or until the beans are very tender.
Save the cooking liquid by draining the beans in a colander placed over a large bowl.
Heat oil and fat in a large skillet over medium-high heat until shimmering. Reduce heat to medium-low and sauté the remaining minced onion until translucent and lightly golden (about 5 minutes). Stir often.
Add 1 clove minced garlic and cook 30 seconds.
Add 1 teaspoon cumin, 1 teaspoon kosher salt and ¼ teaspoon black pepper. Stir well.
Add the beans and cook 2 minutes.
Add 1 cup reserved bean-cooking liquid and mash the beans with a potato masher. Cook until almost all liquid is absorbed or until the
desired consistency. If more cooking liquid is needed, add 1 tablespoon at a time.
Season to taste with salt & pepper.
When ready to serve: sprinkle the beans with cheese, the remaining chopped cilantro and your favorite garnishes.