Place pork tenderloins in crock-pot and sprinkle with spices. Add chilis, lime juice, and orange juice.
Cook on low heat for 6-8 hours or high for about 4 hours. Pork should be easily shreddable when done.
Use two forks to shred pork, adjust seasoning level if desired and simmer another half hour.
Preheat broiler and transfer shredded pork to a baking sheet, spread out in a medium-thin layer, leaving any juices in the crock-pot.
Broil on low for about 5 minutes until it starts to get crisp but is not burnt or dried out. Remove pork and toss with reserved cooking liquid to moisten.
Stir in fresh cilantro and serve with taco fixings or over Mexican flavored rice. Taco fixing ideas: pickled red onions, queso fresco, salsa, cheese, lime, guacamole, tomato, lettuce, black olives or whatever else you prefer.
*The recipe was revised in 2016 to remove beer since it wasn't necessary. You can add about 1/2 cup of beer if you want to.