Mix together flour, cornstarch, and water to make thin batter
When oil is hot, coat half of wings in batter and drop into oil allowing batter harden before releasing into oil. Cook for 7 minutes until chicken starts to turn brown. Remove to a wire rack to cool, and cook remaining chicken the same way.
When all the chicken has been fried once and cooled for 5 minutes, raise oil to 375°F. When oil gets to temperature, return all chicken to oil and cook for another 7 minutes. Remove from oil and cool.
To make sauce, first combine sesame oil, garlic, and ginger and microwave for 40-60 seconds until aromatic but not brown. Remove from microwave and add water, sugar, gochujang, and soy sauce.
Coat fried chicken with sauce by tossing in bowl then allow sauce to dry for a minimum of 2 minutes before serving.