Dry off the pork butt pieces with paper towels. Heat up the body of the pressure cooker over a medium flame. Melt 2 Tbl of lard in it. Sear the butt pieces off in the lard. Remove the meat and degrease the pan. Throw the water, cumin, garlic and salt and pepper to taste into the cooker. Return the butt pieces to the pan. Turn up the flame to high. Place and lock the lid on the pressure cooker. Allow the gizmo to come up to its default pressure. After it reaches pressure, turn the flame down to medium and listen to the pressure cooker. When it begins to hiss and spit, turn the flame down to about medium, allowing a slow, constant stream of vapor to spew. Continue pressure-cooking at this temperature for 30-35 minutes. Turn off the flame and allow the cooker to de-pressurize without external intervention. Remove the pieces of the butt from the pressure cooker.
Preheat oven to 450 degrees F.
Break up the now slightly cooled pork pieces in half. Do not shred, as they will cook again. Place them on a cookie sheet, in a single layer. Roast the pork in the oven for 10-15 minutes, until they takes on color and crispiness, turning several times.
Place the pork chunks into pre-warmed tortillas, along with an amount of cilantro to your liking. Fold them over taco-style. Serve with green chile salsa.