Place pork in a large cast-iron pan. Sprinkle with paprika, granulated garlic, and cumin.
In a small bowl, combine mustard and sugar. Add mixture to pork and rub in, making sure entire piece of meat is evenly coated with the rub.
Pour a can of beer into the pan and cover pan with foil. Place in oven and roast for 3 to 3 1/2 hours until pork falls apart. Using 2 forks, shred meat in pan.
For the first tortilla dough, combine 1 3/4 cups masa, garlic powder and 1 1/4 cups water. Form dough into a ball, wrap in plastic wrap and set aside.
For the second tortilla dough, combine 1 3/4 cups masa, cumin, paprika and 1 1/4 cups water. Form dough into a ball, wrap in plastic wrap and set aside.
For the third tortilla dough, combine 1 3/4 cups masa, lime juice, Sriracha and 1 1/4 cups water. Form dough into a ball, wrap in plastic wrap and set aside. Allow all tortilla doughs to rest for 1 hour.
Divide dough balls into 10 pieces. Roll each piece into a ball. Cut a large plastic baggie along 3 seams. Lay flat and place a ball in the middle. Cover with the other side of the baggie. Using a 10-inch skillet, push down evenly to flatten.
Heat a cast-iron skillet over medium heat. Working in batches, cook the tortillas until cooked through, about 6 minutes. Place tortillas on a plate, cover with a towel and set aside.
On the stove, turn the flame on medium-high and place tomatoes directly over the flame. Rotate pepper with tongs to char the skin on all sides, about 20 to 30 seconds. Continue with the jalapeño. Remove to cutting board.
Coarsely chop both the tomato and the jalapeño and add to a medium bowl. Grate the onion into the same bowl. Add the garlic, cilantro, cumin, lime juice and salt and mix well. Place in refrigerator for at least 1 hour for flavors to meld.
Build tacos using tortillas, meat, and assorted toppings.
