Heat oil in a skillet over high heat. Add pork; cook and stir just until meat is browned on all sides, about 5 minutes.
Place meat in a 4-quart slow cooker. Pour enchilada sauce over the meat. Top with hominy, onion, chilies, garlic, cayenne pepper, and oregano. Pour in enough water to fill the slow cooker.
Cover and cook on High for 6 to 7 hours. Stir in cilantro and salt. Cook on Low for 30 minutes more.
