Pulse garlic, onion, oregano, cumin, chile pepper, salt, and pepper together in a blender, pouring in vinegar and enough olive oil until mixture is pasty. Scrape down sides of the blender as necessary to fully incorporate. Spread this mixture all over the pork loin, and place into a slow cooker.

Cook on Low until the pork is fork tender, 6 to 8 hours. When ready, cut the pork into chunks, or shred; garnish with lime wedges to serve.