In a medium bowl, combine the soy sauce, sesame oil, ginger, garlic, honey (or maple syrup), and rice vinegar. This will be your marinade. Add the cubed chicken and let it marinate for at least 30 minutes.
In a small bowl, mix the cornstarch and water together to create a slurry. Set aside.
Heat a large non-stick skillet or wok over medium-high heat. Add the marinated chicken (discard the marinade) and cook for about 5-7 minutes until browned and cooked through, stirring occasionally.
Add the broccoli, red bell pepper, and carrot to the skillet. Stir-fry the vegetables with the chicken for another 4-5 minutes until they are tender-crisp.
Pour the cornstarch slurry into the skillet and stir quickly to coat the chicken and vegetables. Cook for an additional 1-2 minutes, allowing the sauce to thicken.
Sprinkle sesame seeds over the top and toss everything to combine.
Serve the sesame chicken over cooked brown rice or quinoa, garnished with chopped green onions.
Notes
For a sweeter option, use honey or maple syrup as preferred.