In a medium bowl, toss the chicken pieces with cornstarch until evenly coated.
Heat vegetable oil in a large skillet or wok over medium-high heat. Add the chicken and cook for about 5-7 minutes, stirring frequently, until browned and cooked through. Remove the chicken from the skillet and set aside.
In the same skillet, add broccoli, bell pepper, and snap peas. Stir-fry for about 3-4 minutes until the vegetables are tender-crisp.
Add garlic and ginger to the skillet and cook for an additional 1 minute, stirring constantly.
In a small bowl, whisk together soy sauce, honey, sesame oil, and rice vinegar. Pour this sauce over the vegetables in the skillet.
Return the cooked chicken to the skillet and toss everything together until well coated and heated through, about 2 minutes.
Sprinkle sesame seeds over the stir-fry before serving. Serve hot over cooked rice.