In a small saucepan, combine soy sauce, brown sugar, honey, rice vinegar, minced garlic, and freshly grated ginger. Heat over medium heat, whisking for 3-4 minutes until sugars dissolve and sauce is fragrant.

In a small bowl, mix cornstarch and water to create a slurry. Gradually pour this into the Teriyaki sauce, stirring constantly. Return to medium heat and simmer for another 3-4 minutes until thickened.

Cut boneless chicken into bite-sized pieces. Season generously with salt and pepper. Let them sit for a few minutes while heating the skillet.

Heat vegetable oil in a skillet over medium-high heat. Add the chicken in a single layer and cook for 6-7 minutes on each side until golden brown and fully cooked.

Reduce heat to low and pour the thickened Teriyaki sauce over the chicken. Gently stir to coat each piece and simmer for 2-3 minutes.

Serve over steamed rice, garnishing with sesame seeds and green onions. Pair with steamed broccoli if desired.