In a bowl, combine 3 tablespoons cornstarch, 1 teaspoon salt, and 2 tablespoons cooking oil.

Coat the shrimp with the cornstarch mixture and set aside.

Thaw the green beans in lukewarm water and drain.

In a small bowl, stir together soy sauce, sugar, sherry (optional), chicken stock, and the remaining 6 teaspoons cornstarch.

Heat a wok or large pan over high heat for at least 20 seconds.

Add the remaining 1 1/2 cups of oil to the wok and heat to about 250°F.

Add the shrimp and cook for about 30 seconds, or until no longer pink.

Remove the shrimp from the wok using a slotted spoon and set aside.

Keep the remaining oil in the pan.

Add the minced garlic and ginger to the wok.

Stir-fry quickly for 10 seconds.

Add the soy sauce mixture to the wok and cook until thickened.

Add the green beans and water chestnuts to the wok and stir-fry for 30 seconds, or until heated through.

Add the shrimp to the wok and mix until they are evenly coated with the sauce.

Serve over white rice or lo mein noodles.