Salt and pepper roast liberally. Place the roast in a slow cooker and top with the onion, orange and spices. Add about 2 cups water or stock to slow cooker. Cover and cook on low for 8 to 10 hours or on high 4 hours. Reserve liquid.
Once the meat is tender, remove from slow cooker and let cool slightly before pulling apart with a fork. After you shred the meat pour some of the pan juices on it so that the meat stays moist.
Optional
In a large saute pan, heat the olive oil over high heat. Press the carnitas into the oil and fry until crusty on one side.
Place about 1/2 inch olive oil in a small pan over high heat. Fry tortillas on one side for about 1 minute. Turn and fold in half. Fry on first side of folded tortilla then turn and fry on the other.
Place meat in tortilla. Serve with your favorite toppings. Lettuce, tomato, cheese, salsa, etc..
Notes
Leftover meat can be refrigerated for 3-4 days.Reheat in microwave until hot.For longer storage, freeze up to 2 months.Thaw in refrigerator. Reheat per above instructions.