Rinse the beans well in a colander, and dump into the crockpot. Add enough water so the beans are fully immersed, with two to three inches of water on top. Put the lid on your crockpot. Do not turn on.
Let them soak overnight.
In the morning, drain and rinse the beans under cold running water. Put them back in the crockpot with enough clean water to cover the beans with about an inch of water. Stir in the cumin and coriander. Peel and cut the onions in half, and put them in the crockpot. Peel all of the garlic, but toss them in whole. Add the jalapeÃ±o pepper.
Cover the crock and cook on low for 8-10 hours, or until the beans are tender. Fish out the onion. If the beans are soft and you still have a bit of liquid left, carefully drain it, saving a little to help with the smooshing and for added flavor.
Using a potato smasher, or hand mixer, mash the beans. You can just start using the beans, or you can scoop hunks of smooshed beans out of the crock and fry them on the stove top with a bit of butter or olive oil. Season to taste.