Thinly slice the pork.
In a food processor or blender, combine one of the pineapples and the rest of the marinade ingredients. Blend until smooth. (You will probably have to do it in batches.)
Marinate the sliced meat in the marinade for at least four hours.
Pan fry, grill, or broil the meat and the spears of the second pineapple. Roughly chop cooked meat and pineapple.
Serve pork and pineapple on tortillas with sliced red onion, chopped cilantro, and lime wedges.