Rinse and dry the pork shoulder roast with a paper towel. Salt and pepper liberally.
In a small dish, combine the oregano, cumin, chili powder, and olive oil and rub all over the shoulder roast. Place pork roast inside the slow cooker. Toss in onion, garlic, and jalapeño. Squeeze orange halves into the slow cooker and add them in.
Cook the pork:
Cover and cook for 8 to 10 hours on low or 4 to 5 hours on high. Once the meat is tender, remove it from the slow cooker onto a large cutting board and allow the meat to cool down prior to shredding it between two forks.
For crispy, charred carnitas, you can pan-fry the roast. Heat vegetable oil in a large pan. Once hot, add the meat in batches and sauté until some of the edges are crusty. This step is optional.
Assemble the wraps:
Assemble the lettuce wraps and garnish with your favorite toppings.
Notes
Nutrition information is calculated for 2 lettuce wraps without toppings.