Before you plan to cook the pork, take it out of the refrigerator for 15 minutes. In a small bowl, mix together kosher salt and chipotle powder and rub in into the pork, being sure to cover the entire surface of the meat with the mixture. Put the pork in heavy covered cooker, Dutch oven, or roasting pan. Allow it to sit for one hour before you put it in the oven.  

 Place in the oven. Turn the heat to 275 degrees.  Cook until the pork falls apart when you press it with the back of a fork—approximately 3-1/2 to 4 hours or about an hour per pound.  Remove it from the oven and let it rest covered for 15 minutes. (Of course, you can also cook this in your Crock-Pot or slow cooker)

For the tortillas: Heat the tortillas on a medium-hot griddle, turning them frequently, until they are warmed through and soft (or heat them in the microwave covered with a damp paper towel).  Wrap them in a towel and place in a basket.  Transfer the pork to a large serving platter and use tongs or two forks to shred into chunks.  Add the lime wedges to the platter, place the cilantro in a small serving bowl and serve immediately, with the warm tortillas on the side.

To fill the tortillas, double them up so they don’t tear apart; place one on top of another on a plate, spoon some of the pork on top, squeeze a little lime juice over the pork, sprinkle some cilantro on top and fold in half.

Source: Martie Duncan