Preheat oven to 300 deg f. Fetch a 9x13 pan (or whatever you have really).

Cube pork into 2 inch chunks, put in pan. Quarter the onion, put in pan. Juice the orange and put that, and the leftover rind, in the pan. The garlic/cinnamon/cumin/salt/pepper/chili flake/water goes... in the pan. Stir to combine everything, and cover tightly with aluminum foil.

Bake pork for 2.5-3 hours, or until tender. Once cooked, remove pork from pan and place on baking sheet (save that liquid in the pan). Set broiler to high and broil for 3-4 minutes or until pork is super crispy. Roughly chop and pour 1/2 cup of the baking liquid over the meat. Serve on tortillas topped with the pineapple/onion/cilantro.