Measure out and place minced garlic, minced ginger and red pepper flakes in a small bowl. Set aside.
Measure out and combine sugar, brown sugar and orange juice in another bowl. Set aside.
Measure out and combine vinegar and soy sauce in another small bowl. Set aside.
In a small bowl measure out and stir together ¼ cup water with 2 tablespoons cornstarch. Set aside.
Heat 2 tablespoons vegetable oil in a saucepan over medium heat.
Once the oil is hot add, the minced garlic, ginger and red pepper flakes. Cook and stir constantly for about 30 seconds until fragrant.
Whisk in the sugar, brown sugar and orange juice and cook for 3-4 minutes, stirring often until heated through and sugars are dissolved.
Whisk in the vinegar and soy sauce.
Stir in the cornstarch slurry. Cook and stir the sauce until it thickens to the consistency of honey. (Sauce will continue to thicken a little more as it cools).
Whisk in sesame oil and heat through.
Remove from heat and set aside while you fry up the chicken pieces.