Pick through the dried beans and discard any debris or shriveled beans. Rinse them thoroughly under cool running water; an overnight soak is optional, since this slow cooker method is designed to cook the beans without soaking.

Place the rinsed beans, smoked ham hock, chopped onion, garlic, chili powder, black pepper, and eight cups of water or low-sodium chicken broth in a 6-quart slow cooker. Hold back the tomatoes, lemon juice, and most or all of the salt until the beans are nearly tender.

Cover and cook on LOW for 7 to 8 hours or on HIGH for 4 to 5 hours. The soup is ready for the next step when the beans are tender and the ham pulls easily from the bone.

Add the diced tomatoes with their juices during the final hour of cooking. Adding them late helps prevent the acidity from slowing the softening of the beans.

Remove the ham hock from the slow cooker and let it cool enough to handle. Pull the meat from the bone, discard the skin and bones, and return the shredded meat to the soup.

Stir in the included seasoning packet, if provided, and one tablespoon of fresh lemon juice. Taste carefully, then add the one teaspoon of salt and more only as needed, because the ham and seasoning packet may already be salty.

If the soup is thicker than you prefer, stir in hot water or broth until it reaches the desired consistency. Ladle into bowls and serve hot with crusty bread or your favorite simple toppings.