Mix together the chili powders, cumin, salt and pepper. Stir in the liquid smoke. Rub this mixture all over the pork and place it a large slow cooker. If there is excess spices save and toss on the onion and garlic. Place in onion, garlic and pour in orange and lime juice. Cover and cook for 8 hours on low or 4-5 hours on high.
If making ahead, shred pork with two large forks, cool, cover and refrigerate. When ready to serve place the shredded pork on a rimmed baking sheet. Broil until crispy and heated through.
Serve on a heated tortialla with your favorite toppings of cole slaw, guacamole and pico de gallo or salsa.
Nutrition calculation is an estimation only. If you need nutritional calculations for medical reasons, please use a source that you trust.