Cook 1 cup rice per package directions.
Chop 2 bell peppers and 1 onion. Cut 1 pound boneless skinless chicken breasts into 1-inch pieces. Thinly slice 2 scallions. Set aside.
Heat 1 tablespoon oil in a nonstick skillet on medium. Add the peppers and onions and cook, stirring occasionally, until tender, 6 to 8 minutes; transfer to a bowl.
Meanwhile, in large bowl, toss the chicken with 3 tablespoons cornstarch. Add another tablespoon oil to same skillet and cook the chicken, stirring occasionally, until cooked through, 5 to 7 minutes.
In another bowl, whisk 2 tablespoons soy sauce, 2 tablespoons rice vinegar, 1 tablespoon Sriracha, 1 tablespoon honey, and 1 teaspoon toasted sesame oil. Finely chop 2 cloves garlic and a 1-inch piece fresh ginger, and add to bowl.
Return the vegetables to pan. Then add in the sauce and ⅓ cup water; simmer until slightly thickened, about 2 minutes. Sprinkle with 1 tablespoon sesame seeds and the sliced scallions. Serve over rice.
