Check the beans for debris, and rinse in several changes of water.
Place the beans in the slow cooker and add enough water to cover by about 2 inches. Add minced garlic, chopped onion, dried oregano, and/or a bay leaf. (You can also add bits of vegetables that you'll discard after the beans are cooked, as if you are making a stock. Use celery, leek tops, carrot chunks, fresh parsley, green onion — whatever is in your crisper at the time.)
Add a splash of olive oil and a generous amount of salt. (Recommend 2 teaspoons of salt for 1 pound of beans.)
Cover the slow cooker with the lid, and cook the beans on high heat — 3 to 4 hours for soaked beans, or 4 to 5 hours for unsoaked. Check occasionally for doneness to avoid overcooking.
Once the beans are fully cooked, remove the lid, give a stir, and allow them to breathe and reduce for another hour, if you can.