In a medium size bowl, place the dried chilies along with a few cups of very hot water. Allow the chilies to soak until soft, about 5-10 minutes. When the chiles are tender, remove them, cut them open and scrape out the seeds.
Meanwhile, cut the pork roast into thin bite-size pieces, removing any excess fat. Place into a large ziploc bag.
In a blender, add the soaked chilies, garlic cloves, red onion, apple cider vinegar, lime juice, pineapple juice, 1½ cups chopped pineapple, oregano, cumin, coriander, paprika, cayenne and salt. Puree until smooth, then pour into the ziploc bag, zip and shake to coat. Refrigerate the pork for 4 hours, preferably overnight.
After the pork has marinated, place it into a colander (sitting in the sink) and allow the mixture to drain (you want the pork to be coated but not super saucy).
In a large skillet set over medium-heat, add ½ tablespoon of olive oil. Once hot, add half of the pork, cook for 3-4 minutes (or until thoroughly cooked), flipping half way through. Repeat with the remaining olive oil and pork.
Serve in crispy or soft corn tortillas, garnish as desired.
Notes
*I used a can of Dole 100% pineapple juice and measured it out. -The pork isn't super spicy, just flavorful. If you want extra heat, add an additional ¼ tsp. cayenne pepper.