Place a wok over medium heat. Add 1 tablespoon oil and when hot, add the ginger and green onions, and stir-fry until aromatic, about 1 minute. Add the shrimp and water chestnuts and cook for 1 minute. Add the soy sauce, sugar, sesame oil and chili oil and stir to combine. In a small bowl, combine the cornstarch and water and add to the shrimp mixture, stirring. (The mixture should thicken immediately.) Transfer to a bowl or plate and let cool before assembling the won tons.

Keeping the won ton wrappers covered with a damp kitchen towel, place 1 won ton wrapper at a time on a work surface with 1 point toward you. Spoon a rounded tablespoonful of filling in the center, just above the point. Fold the corner over the filling and roll to tuck the point under. (The won ton should look like a triangle). Pinch the wrapper around the filling to completely enclose, pushing gently to expel any air bubbles. Using both hands, pull the 2 side corners toward you below the filling. Overlap the corners slightly, moisten with a dab of water, and pinch to seal.

Place the filled won tons on a baking sheet and cover with a damp cloth while preparing the remaining won tons. (If desired won tons can be frozen on a baking sheet and once frozen, kept in a ziplock bag for up to 2 months.)

Fill a large pot or electric fryer halfway with vegetable oil and heat to 375 degrees F. Add the won tons in batches and fry until golden on both sides, about 2 minutes. Remove with a slotted spoon and drain on paper towels. Serve hot with soy sauce and/or Chinese hot mustard.