In a large deep pan, place the pork and fill with water until just covered. Bring to a boil, then reduce to a simmer, stirring occasionally, for about 40 minutes, until the water has evaporated. Increase the heat to medium-high, season with salt and pepper, and continue cooking for about 10 minutes. Remove the meat and, using two forks, tear the pieces. Serve in tortillas with toppings.