Place pork in the base of your slow cooker. In a small bowl, stir together all remaining ingredients. Pour evenly over pork. Cook on low for 8 hours. When done, shred the pork using two forks, pulling against the grain of the meat. Serve in warmed tortillas with shredded lettuce, sliced bell peppers, chopped tomatoes, black olives, grated cheddar cheese, and sour cream. Garnish with chopped scallions.