In a medium bowl, whisk together soy sauce, mirin, brown sugar, honey, rice vinegar, sesame oil, minced garlic, grated ginger, and red pepper flakes. Add chicken pieces to marinade, ensuring well coated. Cover and refrigerate for at least 30 minutes, or up to 4 hours for maximum flavor.

In a small bowl, whisk together cornstarch and water until smooth to create a slurry for thickening the teriyaki sauce.

Heat vegetable oil in a large skillet or wok over medium-high heat. Remove chicken from marinade, reserving the marinade. Add chicken to hot skillet in single layer and cook for 5-7 minutes until browned on all sides and cooked through.

Pour reserved marinade into skillet with chicken. Bring to a simmer, then slowly pour in cornstarch slurry, stirring constantly. Cook, stirring frequently, until sauce thickens to desired consistency, about 1-2 minutes. Remove from heat and set aside.

Preheat oven to 375°F (190°C). Wash bell peppers thoroughly. Cut each pepper in half lengthwise from stem to bottom. Remove seeds and membranes from inside peppers.

Optional: Bring large pot of water to boil. Add pepper halves and cook 3-5 minutes. Remove and immediately plunge into ice water to stop cooking. Drain well (this step softens peppers).

In a large bowl, combine cooked rice, shredded carrots, thawed peas, chopped water chestnuts, chopped cilantro, lime juice, salt, and pepper. Mix well.

Fill each pepper half with rice mixture, packing firmly. Top each pepper with generous amount of prepared teriyaki chicken.

Sprinkle shredded mozzarella cheese evenly over top of stuffed peppers.

Arrange stuffed peppers in baking dish. Add about 1/2 cup water to bottom of dish to create steam and prevent drying.

Cover with aluminum foil and bake for 25-30 minutes. Remove foil and bake additional 5-10 minutes until cheese is melted and bubbly and peppers are tender.

Let stuffed peppers rest for a few minutes before serving. Garnish with additional green onions and sesame seeds if desired.