Toss chicken with cornstarch, salt, and pepper in a bowl until evenly coated.
Heat oil in a large skillet over medium-high heat. Add chicken and sear until golden brown and cooked through, about 6-8 minutes.
In a small bowl, whisk together soy sauce, honey, rice vinegar, garlic, and sesame oil.
Pour sauce over the chicken in the skillet and stir until the sauce thickens and coats the chicken, about 2-3 minutes.
Sprinkle with toasted sesame seeds and green onions.
Serve hot over steamed rice.