Combine garlic, soy sauce, water, honey, 1 tablespoon oil, cornstarch and black/red pepper. Stir chicken into marinade and mix to coat.
Cover and refrigerate at least 2 hours, stirring once to twice.
In large skillet, heat remaining oil.
Using slotted spoon, transfer chicken to skillet. Stir-fry about 5 minutes. Add reserved marinade; continue to cook and stir about 30 seconds until thickened.
Remove to platter. Garnish with green onion. Serve with snow peas, if desired.