Heat large skillet over medium-high heat. Cook pork until browned. Stir in mushrooms, ginger, garlic, water chestnuts and chili sauce; cook about 5 minutes or until vegetables are tender. Remove from heat; stir in oyster sauce and 3 tablespoons cilantro.
To make the pickled ginger vinaigrette, mix all ingredients until well blended.
To serve, serve pork mixture in lettuce cups with pickled ginger vinaigrette on the side.
Yields 4 portions.