Place pork belly in a glass baking dish and rub evenly with granulated sugar and Kosher salt. Cover with plastic wrap and refrigerated for at least 12 hours and up to 24 hours. Remove from refrigerator and discard plastic wrap, pat dry and remove any liquid that has accumulated. Rub with ancho chili powder. Preheat oven to 450°F. Roast pork belly for 30 minutes, then lower heat to 275°F and roast for 1 hour more, until pork belly is tender.
Let pork belly cool slightly, then slice into approximate 1/2″ slices. If you want perfectly clean slices: cool pork belly completely, then remove from baking dish and wrap in aluminum foil. Refrigerate until cold. Slice pork belly, then reheat in oven at 275°F wrapped in aluminum foil until heated through.
Top tortillas with a couple slices of pork belly, chopped avocado, ancho chili roasted pineapple, pickled onions, and a sprinkle of queso fresco and cilantro. Serve with lime wedges and preferably a margarita. Devour.
for the Ancho Chili Roasted Pineapple
Heat oil in a medium skillet over medium high heat. Add pineapple, sugar, and ancho chili powder and stir to coat. Cook, stirring occasionally, for 4-5 minutes, until pineapple caramelizes with a nice golden brown color.
for the Pickled Onions
Combine vinegar, water, sugar, and salt in a medium bowl. Whisk together until sugar and salt is fully dissolved.
Place onion in a jar or bowl (I like to use a mason jar). Pour vinegar mixture over the onions and let sit at room temperature for at least 1 hour if you’re in a rush. Preferably, cover jar or bowl and place in refrigerator for at least 1 day. Pickled onions will last for a couple weeks stored in the refrigerator.