Combine beans, water, garlic, onion, 1 teaspoon cumin, 1 teaspoon salt and 1/2 teaspoon pepper in a slow cooker. Cook on low at least 6 hours, until beans are very soft.
Drain water, reserving the liquid.
Using a potato masher, mash the beans. Add enough reserved liquid to meet your consistency preference.
Add remaining 1 teaspoon cumin, 1/2 teaspoon black pepper and chili powder, garlic powder, onion powder and 1/2 teaspoon salt. Add more spices to taste!