Combine pork, water chestnuts, green onions, soy sauce, cornstarch, salt and ginger in medium bowl; mix well. Place 1/2 teaspoonful pork mixture in center of each wonton skin. Fold wonton skin over filling to form a triangle. Turn top of triangle down to meet fold. Turn over; moisten 1 corner with water. Overlap opposite corner over moistened corner; press together firmly.
Heat oil in wok or large saucepan over medium-high heat to 375 degrees F. Deep-fry wontons, a few at a time, 2 to 3 minutes, or until brown and crispy. Drain on paper towels. Serve warm with ketchup and mustard or sweet & sour sauce, as desired.