Step 1Soak beans overnight in enough cold water to cover by several inches. Drain beans and set aside.
Step 2Fry bacon in skillet over medium heat until crisp, 5 minutes. Drain on paper towels and set aside.
Step 3Pour off all but 2 or 3 tablespoons of bacon fat, add onion and cook until golden brown, 8 to 10 minutes. Add garlic and cook 1 minute more.
Step 4Add beans, 8 cups water, tomato paste, chorizo, red pepper flakes and paprika. Cover and simmer until beans are tender, 1 1/2 to 2 hours, stirring occasionally to prevent scorching. Just before serving, crumble bacon into beans and season with salt and pepper.