Marinate pork belly slices with garlic, taco seasoning, garlic powder, orange juice, lemon juice, bay leaves, oregano, salt, and onion salt. Marinate at least 2 hours but overnight is best.
Place the pork belly and all the marinade into a baking dish. Cover with foil and braise 60 mins at 350 degrees. Then remove liquid and allow pork belly to cool completely.
When pork belly is cooled, cut into 2 inch pieces. Pan fry on medium low heat for 3-5 mins each side until crispy. No oil necessary because the pork belly will start to release its fat when heated.
Set aside crispy pork belly.
Pickled onion
Boil 2 cups water. Then add in salt, sugar, vinegar, and mix thoroughly until sugar and salt are completely dissolved. Then add in onions. Allow to sit in the pickling liquid for at least 1 hour. For best results, refrigerate pickled onions overnight and serve the next day.
Assemble Tacos
Serve pork belly on warm tortillas. Top with pickled onion, avocado, cilantro, and salsa.
Heat a frying pan on medium heat. When hot, add in tortillas one at at time, allowing them to soften and become very light brown. Remove them from the pan and place onto a covered plate to keep them soft and moist.
Assemble tacos: place down a tortilla, then top with a few pieces of crispy pork belly. Then top with jarred salsa, cilantro, avocado, and a few slices of pickled onion.