Here's what my MIL (who is mexican) taught me...easy and fool proof!
Take the pinto beans (2 Cups) and sift through them before putting in the slow cooker (Reason: sometimes there are stones and icky beans in there and you don't want to chip a tooth).
Add Garlic cloves...I put in 8 large cloves(Peel).
Cover with hot water.
Turn slow cooker on for 3-3 1/2 hours...DO NOT ADD SALT--beans do not get tender with salt in the water.
Once the beans are soft then add salt to taste (I use about a tablespoon).
Next remove beans from the slow cooker...mash.
Then add shredded cheese. I use a mix of montery jack and cheddar.
You can eat these as is (a little healthier if you're watching cholesrol).
OR..........
Heat about 1/8th cup of oil or lard in a large frying pan. Once hot, add the mashed beans. Watch out for splattering. Stir beans around until they absorb the oil. Delicious every time.
Good luck