In a small bowl, mix together the salt, pepper, ground cumin, chili powder, and oregano. Rub the mixture all over the pork shoulder.
Add the pork shoulder, orange juice, and lime juice to the crockpot. Sprinkle the minced garlic on top.
Cover and cook on low for 8-10 hours.
Remove the lid and shred the pork with two forks.
Preheat oven to broil. Line a baking sheet with aluminum foil (for easy clean up) and place the shredded pork on the baking sheet. Add a few tablespoons of the juice from the crockpot over the shredded pork (optional, but I prefer to do it).
Broil for 5-10 minutes or until the edges are browned.
Serve with flour or corn tortillas and toppings of choice.