Trim fat from pork. Cut pork into 1/2-inch cubes. In a large skillet brown half of the pork in hot oil. Transfer meat to a 3-1/2- to 4-1/2-quart slow cooker. Brown remaining meat with onion. Drain off the fat and transfer meat and onion to the slow cooker.
Add water, potatoes, hominy, chile peppers, tapioca, garlic salt, salt, black pepper, cumin, and oregano. Cover; cook on low-heat setting for 7 to 8 hours or on high-heat setting for 4 to 5 hours. Garnish with snipped cilantro, if desired.