Toss chicken pieces with salt, pepper, and 1 tablespoon cornstarch.
Heat vegetable oil in a large skillet over medium-high heat. Sear chicken for 4–5 minutes, until golden and cooked through. Remove and set aside.
In the same skillet, add garlic and ginger, sauté for 30 seconds.
Stir in soy sauce, bourbon, brown sugar, ketchup, vinegar, and red pepper flakes. Bring to a simmer.
Return chicken to the skillet and toss to coat in the sauce. Simmer for 5–7 minutes.
Stir in the cornstarch slurry and cook 1–2 more minutes, until the sauce thickens and turns glossy.
Garnish with green onions and sesame seeds. Serve over rice.