Start by making a rub for your pork. In a small mixing bowl mix cumin, oregano, smoked paprika, salt, and pepper, together. Then rub the seasonings over all sides of the pork.
Place the pork in the slow cooker. Making sure that the fat side of the pork is facing up.
Over the top of the pork spread on your minced garlic, green chilis, and onions. Add the juice from the oranges and limes.
Cover and cook on low 10 hours.
Remove the meat from the slow cooker and with two forks pulling away from each other shred your cooked pork.
Once shredded place your pork back into the slow cooker and let it cook on low for 30 minutes. (Tip: If there seems to be a lot of juices, you can remove some of it first)
After simmering the meat, using tongs, transfer the meat to a large rimmed sheet pan. Make sure the pan is large enough that the meat is not crowed but has room to spread out.
Place it under the broiler for 1-3 minutes. This cooks quickly so make sure to watch it closely. You want some of the meat to brown up and become crispy, but not all of it.
Serve with your favorite toppings and enjoy.