Place all in slow cooker and cook on high for about 4-6 hours.
When the beans have cooked, drain while reserving the liquid. Pour beans into a big bowl, and mix with a hand mixer, or a masher. Add as much of the reserved water (and a little extra salt) as needed to attain desired consistency. For extra flavor add jalapenos, some pepper, or even cayenne if you like your beans more spicy.
If you store this, reconstitute as necessary if the beans get too thick upon sitting in the fridge.