1. For the brine, heat liquid, salt and pepper to a bowl in microwave safe bowl. Stir to make sure salt is dissolved. Add ice cubes to cool brine at least to room temperature. Add pork, cover and let sit overnight in the refrigerator.
2. Preheat oven to 350.
3. Dry pork off, cut into 1" cubes and salt thoroughly. Brown pork in a heated roasting pan or large oven proof skillet over medium-high heat, 8-10 minutes. Remove pork pieces. Add beer, lime juice, and spices, scraping to remove any browned bits on the bottom of the skillet.
4. When the liquid begins to thicken, add the pork pieces into the sauce. Add water until it almost reaches the top of the pieces. Place into the oven and braise an hour.
5. Check to add more water to same height. Braise for another hour or until pork crumbles when pressed (it will look dark and almost burnt, but trust me, its not).
6. Serve with spiked guacamole, lime quarters for squeezing on tortillas, and finely diced roma tomatoes.
Combine all ingredients in container for blender or food processor. Puree ingredients and taste to adjust salt if needed or add additional lime juice as desired.