Use a good sized covered pot. Chop onions, mince (or press) peeled garlic, chop red pepper (I use about half, but you could use more, depending on the amount of beans you use), chop cilantro, reserving some for garnish. This onion/garlic/pepper combo is called the 'sofrito.'
Open tins of beans, drain most of the liquid off. Some people use dried beans, soak them overnight and cook them until they're done. I use canned ones. Much easier and faster.
Saute onions in bacon fat, olive oil, or canola oil until somewhat soft - about 5 minutes, perhaps more. Use enough oil so the onions stay moist. It's tastiest to use bacon fat, and you can either eat the bacon separately or chop it and add to the dish along with the beans. For vegetarians - or if you don't have or like bacon, use olive or canola oil.
After about 5 minutes, add the garlic. It doesn't take long to impart its flavor and you don't want it to burn. Add the red pepper and saute a few more minutes.
Add as many tins of black beans as you'd like - at least 4 of the regular size, up to 4 of the jumbo size(if you use more than that, also use more onions, garlic, and pepper). The proportions are very flexible. This dish lasts a few days, so I always make a lot.
Stir everything together and add the chopped cilantro.
If you'd like it to be more of a substantial dish, add a ham hock. As it cooks, it adds tremendous flavor and some of the meat falls off. You may need to add water later - you can even add lots of water or stock to make it a soup. Cover and cook over a low flame for about 45 minutes to an hour so the flavors all blend together.
Taste. If you haven't used the bacon or ham hock, it will need salt and pepper to taste. Some people add a Tablespoon or 2 of sherry or balsalmic vinegar. Serve hot with rice. It's great with any roast meat, fish, or eggs.