Place the pork shoulder in a large dish or resealable bag.
In a mixing bowl, whisk together orange juice, lime juice, olive oil, garlic, oregano, cumin, salt, and black pepper.
Pour the marinade over the pork, ensuring it is fully coated. Cover and refrigerate for at least 2 hours or overnight for deeper flavor.
Transfer the marinated pork and marinade to a slow cooker. Cover and cook on LOW for 8-10 hours or HIGH for 4-5 hours until tender and easy to shred.
Remove the pork from the slow cooker and shred using two forks.
Optional: Spread the shredded pork on a baking sheet and broil for 5 minutes for crispy edges.
Drizzle some of the reserved cooking juices over the pork and serve with cilantro and lime wedges.