
To a medium saucepan, add all ingredients except water and cornstarch, whisk to combine, and bring to a boil over medium-high heat.
To a small bowl, add the water, cornstarch, and stir to combine.
Add the water and cornstarch mixture to saucepan, reduce heat to low, and allow sauce to simmer for about 5 minutes while you make the chicken; whisk intermittently.
To a large ziptop bag, add the chicken, cornstarch, salt and pepper to taste, seal, and shake to coat chicken evenly.
To a large skillet, add 3 to 4 tablespoons olive oil, chicken, and cook over medium-high heat for about 5 to 7 minutes, or until chicken has cooked through. Stir and flip intermittently to ensure even cooking. If skillet seems dry while cooking, add an additional tablespoon or two of oil as necessary.
After chicken has cooked though, reduce heat to low, add the sauce, stir to coat evenly, and allow it to simmer for a minute or two.
Optionally garnish with green onions, sesame seeds, and serve immediately.