While the chicken is baking, prepare the sauce.
Don’t walk away from this sauce as it gets very hot when making the caramel base and can burn easily.
In a small bowl, mix together 4 tbsp. soy sauce, 4 tbsp. rice wine vinegar, ¼ cup water, 2 tbsp. toasted sesame seed oil, 2 tbsp. hot chili paste or sauce, ½ tsp. salt, 2 tsp. cornstarch, 3 cloves minced garlic and 3 tbsp. freshly grated ginger; combine thoroughly and set the mixture aside.
In a medium saucepan, over medium heat, boil together 1 cup sugar and 1/4 cup of water.
Watch constantly until the caramel starts to turn a light amber color and you can begin to smell the caramel.
When it reaches this stage, give the other ingredients, in the bowl a quick stir to make sure the corn starch is dissolved and add, all at once, to the hot caramel.
Be careful as this mixture is very hot.
Also, be extra careful, at this stage, as the sauce can foam up considerably, for a few seconds, and it is very hot.
Simmer for only few minutes, remove from the heat and allow to cool down slightly.