In a large bowl, combine the salt, black pepper, cumin, smoked paprika, garlic powder, onion powder, oregano, and chili powder. Rub the spice mixture all over the pork shoulder pieces.

Heat the olive oil in a large skillet over medium-high heat. Sear the pork chunks on all sides until browned, about 3-4 minutes per side.

Transfer the seared pork to the slow cooker. Add the orange juice, lime juice, quartered onion, and smashed garlic.

Cover and cook on low for 8 hours or high for 4 hours, until the pork is tender and easily shredded.

Once cooked, remove the pork from the slow cooker and shred it using two forks.

Preheat your oven broiler. Spread the shredded pork on a baking sheet in an even layer.

Broil the pork for 5-7 minutes, or until the edges are crispy and browned. Keep an eye on it to prevent burning.

Serve the crispy carnitas in tortillas with your favorite toppings, such as cilantro, diced onions, avocado, and lime wedges.