Pat chicken pieces dry with a paper towel to remove excess moisture then add to a medium bowl. Season with salt and black pepper then toss with 1/3 cup cornstarch until fully coated. Set aside.
In a large nonstick skillet or wok heat 2 tablespoon of vegetable oil over medium-high heat. To the hot oil add the chicken in a single layer. Cook for 5-7 minutes or until the juices run clear. Once cooked remove the chicken to a platter using a slotted spoon and keep warm. Set aside.
To the pan add 2 tablespoon vegetable oil, sesame oil, ginger, garlic, and crushed red pepper flakes. Stir constantly over medium-high heat cooking for 30-60 seconds.
Add the chicken stock, soy sauce, light brown sugar, rice wine vinegar, hoisin sauce, ketchup and honey. Whisk to combine cooking until the brown sugar has dissolved.
In a small bowl whisk 2 tablespoons cornstarch in just enough cold water to dissolve, around 2-3 Tbsp. Whisk into the sauce in the skillet. Mix for 2-3 minutes until fully combined and the sauce has thickened. (You can repeat the cornstarch slurry as desired and adjust the amount of honey or soy sauce at this stage.)
Add the chicken back to the skillet tossing to coat with the sauce. Simmer for 1-2 minutes or just until heated through, then remove from the heat.
Serve immediately over rice garnished with green onions and sesame seeds, if desired.