Separate chicken wings at joints; discard tips. Mix egg, 2 teaspoons oil, soy sauce, sugar, salt and five-spice powder; pour over chicken.
Cover and refrigerate 1 hour. Add water to chicken. Stir flour, cornstarch and baking soda into chicken.
Heat oil (1 l/2 inches) in Dutch oven or wok to 350. Fry 4 or 5 chicken pieces at a time about 4 minutes, turning 2 or 3 times, until light brown; drain on paper towel.
Increase oil temperature to 375. Fry half of the chicken pieces about 1 minute or until golden brown; drain on paper towel. Repeat with remaining chicken. Serve with sweet-and-sour sauce or hot mustard if desired.
24 chicken wing pieces.