Preheat pellet smoker to 225 F. Combine kosher salt, coarse ground pepper, paprika, chili powder and cumin into a spice shaker.
Cover your pork shoulder in a thin layer of mustard, then liberally coat in the rub seasoning. Place on the smoker and let smoke for 4 hours.
Remove pork shoulder from pellet grill and increase smoker temp to 350 F. Cut out and remove the bone, then cut into 2 inch cubes.
Place pork into a Dutch oven. Squeeze juice from oranges into Dutch oven, along with guajillo peppers, chopped onions, garlic and bay leaves. Fill with water with about 1-2 inches of room left on the top of the Dutch oven. Cover and place back on the smoker. Cook for about 3 hours.
Remove dutch oven from pellet grill and increase temperature to its highest setting and place a large cast iron skillet inside and cover. Let it heat up for about 10-15 minutes.
Remove pork from the dutch oven and place into a colander to remove any excess fluid. While your pellet grill is heating up to the high temp, now would be a good time to heat up beans and rice!
Once the pellet grill is piping hot, place pork carnitas into the skillet. Let it side and crisp up for about 5 minutes, then begin to break up and turn to crisp up more of the carnitas. Continue until you've reached your desired crispiness.
Serve with rice beans and tortillas. Garnish with onions and cilantro if you like. Makes an awesome tostada too!