Prepare the sauce: In a small bowl, whisk together the soy sauce, honey (or maple syrup), rice vinegar, sesame oil, and crushed red pepper flakes. Set aside.
Cook the chicken: Heat olive oil in a large skillet or wok over medium-high heat. Add the chicken and cook until browned and cooked through, about 6-8 minutes. Remove the chicken from the skillet and set aside.
Stir-fry the veggies: In the same skillet, add a little more oil if needed. Toss in the bell peppers, onion, zucchini, and garlic. Stir-fry for about 4-5 minutes until the vegetables are tender-crisp.
Combine chicken and sauce: Return the cooked chicken to the skillet with the vegetables. Pour the prepared sauce over the mixture and stir to coat everything evenly. Let it simmer for another 2-3 minutes to heat through and allow the sauce to thicken slightly.
Assemble the bowls: Serve the stir-fry mixture over a bed of cooked rice. Garnish with sesame seeds and fresh cilantro.