Clean and pat the pork dry with a paper towel. Place pork in the slow cooker. Add salt, pepper, cumin, oregano to the cooker. Then rub all over the pork. Add orange juice, lime, garlic, onions to the cooker. Optional: Lift one side of the pork up (use a tong or wooden spoon); this will allow the juice to go underneath the meat.
Cook
Boneless butt: cook on low for 8-10 hours or until fork tender. Bone-in butt: 10-12 hours or until fork tender.
Shred the pork with tongs or forks while in the cooker. Discard the bone. Optional: remove the whole pork and place on a bowl/plate. Then use tongs or 2 forks to shred the meat. Set aside. Save the liquid for frying.
Frying or Broil in the oven
Frying: Use an iron skillet or nonstick-pan. Add 1 tbsp oil and heat to medium-high. Add ⅓ of the shredded meat and ⅓ of the liquid to the pan. Cook for 5-8 minutes or until the liquid has evaporated and the meat begins to crisp. Set crisped meat aside. Repeat previous steps at least two more times to crisp the remaining pork. Make sure to flip/turn the meat as you cook to crisp all sides.
Broil: Place shred meat on a baking sheet with liquid. Broil on high for 5-10 minutes or until the meat begins to crisp.
Serve on corn tortillas. Top with cheese, cilantro, lime, salsa, avocado, tomatoes and jalapeños. Enjoy!