Soak the beans overnight. The next day, drain and add beans into a large pot (preferably a Dutch oven).
Add the stock, beer, water and salt pork to the pot and simmer on low for 1 & 1/2 hours. Stir occasionally to prevent from sticking to the bottom of the pot.
Meanwhile, cook the bacon in a large skillet over medium-high heat until crisp. Remove to a paper towel-line plate.
Pour out all but 2 tbsp of the bacon grease from the skillet and then heat over medium heat.
Add the onion, peppers and garlic and cook until soft, about 3 to 4 minutes.
Once the beans have simmered for an hour and a half, add the cooked bacon and sautéed vegetables, along with the cilantro, tomatoes, black pepper, cumin and taste. Add salt if desired (the beans will already be salted from the salt pork).
Simmer for another hour then serve.