Place the onion, garlic, cumin, oregano, chicken stock and enchilada sauce in a 4-quart slow cooker. Add the chicken, hominy and salt, and stir to mix. Cover and cook for 3 hours on high or 6 hours on low.
Serve with toppings (shredded cabbage, sliced radishes, cilantro), if desired, and top with lime wedges.
After adding all your toppings, serve with a side of warm tostadas, tortilla chips or bolillo rolls (a traditional Mexican bread).