Preheat oven to 400 F. Line baking sheet with parchment paper.
Dip chicken breast into the cornstarch and completely coat. Shake off extra cornstarch, then dip into the egg whites and then roll into the panko until fully coated and place on a baking sheet. Repeat until all chicken is coated.
Bake for 15-20 minutes and chicken is a light brown and crunchy. While cooking, make the sauce.
In a large sauté pan, add all of the sauce ingredients, except for the cornstarch.
Over medium heat, bring sauce to a boil. Once the sauce is boiling add in the cornstarch and stir, cook again until sauce begins to boil, stir until thickened. Set aside.
Once chicken is completely cooked, place all the chicken into the sauté pan. Toss chicken in the sauce, making sure all of the pieces are covered.
Serve with rice and garnish with red pepper slices and green onion, if desired.