Whisk cornstarch with 1/4 cup water until smooth
Add remaining water + all remaining ingredients (except shrimp)
Whisk until smooth
Refrigerate or freeze until ready to use (thaw before using)
Heat skillet to medium-high heat and add small amount of oil
Saute shrimp for about 5 minutes or until cooked through
Add about 1/2 of the sauce or as desired and continue cooking for about 2 minutes or until heated through