In a medium bowl, mix soy sauce, hoisin, rice win vinegar, sesame oil, srirracha, brown sugar, garlic, and ginger; whisk well to combine; set aside.In a large skillet sprayed with nonstick spray, add chicken and saute until cooked through, about 7-8 minutes. Remove from skillet and set aside.
Spray skillet with nonstick spray again, add red pepper, onion, zucchini and sauté until just tender, about 3-4 minutes. Add sauce mixture, and stir to combine. Turn heat on high.
Mix cornstarch and water in a small bowl. Once the sauce in the skillet is bubbling, add the cornstarch slurry; stir to combine. Simmer for 30 seconds to 1 minute, or until the sauce thickens. Remove from heat and serve immediately.
Mix water with cornstarch in a small bowl, making sure there are no clumps. Pour into the pan, and stir into the sauce. Heat over medium until the sauce thickens.Add the chicken back to the pan and toss until evenly coated in sauce. Garnish with green onions and sesame seeds and serve immediately.