Soak beans in 1-gallon cold water for 8 hours. Drain when ready to use. In a 2 gallon heavy pot cook the bacon pieces until well done. Do not undercook the bacon. Add 1/2 cup chopped garlic, 3 tablespoon cilantro, and chopped onions to hot bacon. Cook until onions are transparent.
When onions are ready add beans, cumin, and chili powder. Stir and add 1/2 gallon cold water. Turn heat to medium-low. Add salt and stir. Cook beans slowly until fork tender (approximately 1 hour). Stir constantly to avoid burning the bottom. Add tomatoes, the 1 tablespoon of garlic, and cilantro, and serve.