Moo shu shells are similar to flour tortillas; made with wheat or rice flour, they can be found in Oriental markets.
Trim fat from pork, and cut into thin strips. Combine pork and next 5 ingredients (pork through garlic) in a zip-top heavy-duty plastic bag; seal bag, and shake well to coat. Marinate in refrigerator 20 minutes.
Heat moo shu shells according to package directions.
Coat a medium nonstick skillet with cooking spray; and place over medium-high heat until hot. Add pork mixture; stir-fry 4 minutes or until done.
Divide pork mixture evenly among warm moo shu shells. Drizzle hoisin sauce over pork mixture, and roll up.