In a medium size bowl, blend the cumin, chili powder, brown sugar, salt, pepper and 1 1/2 tablespoons of olive oil. Cut the pork into 2” cubes then add to the bowl and toss to thoroughly coat the meat.
Pour the beer OR stock into the slow cooker along with the lime juice, juice from the oranges and their rinds, onion, garlic and jalapeno then add the seasoned pork cubes.
Sprinkle the cilantro over the top then cover and cook on high 3-4 hours (or 6-7 on low) or until the pork is fork tender and shreddable but before it gets mushy.
Remove the pork from the slow cooker and shred using two forks. I prefer a more coarse shred – almost chunky, but shred as fine you like.