Look through and discard any heavily discolored beans or pebbles from the dry black beans. Rinse the beans, place them in a large bowl, and fill the bowl with water. The water line should be 2-3 inches above the beans. Soak the beans overnight or for at least 8 hours.
Drain the water from the soaked beans and rinse them again. Add them to a large pot along with 8 cups of water. Bring the beans to a boil over high heat. Let them boil for 1 minute and then lower the heat to medium. Stir the beans, cover the pot, and let them simmer for 1 hour.
Prepare the seasoning after the beans have cooked for 45 minutes. Heat a small, nonstick sauté pan over medium heat. Add the onions and sauté them for 3 minutes or until they soften. Add the garlic, salt, pepper, and cumin. Let this cook for 2 more minutes.
Stir the seasoned onion mixture into the beans and cover them back up. Cook them for about 20-40 more minutes, then check their tenderness. Cook them until they are softened, but not mushy. Generally, beans should be ready in less than 2 hours.
Enjoy them right away, save them for later, or add them to another dish. You may want to add more seasoning according to your preference and garnish them with toppings such as cilantro, jalapeños, and lime juice.