In a steamer set over boiling water, steam asparagus, covered, until just crisp-tender, about 1 to 2 minutes. Transfer asparagus to a colander and rinse under cold water to stop cooking. Drain asparagus well.
In a 1-cup measure, stir together cornstarch and water until dissolved and stir in soy sauce, Sherry or Scotch, sugar, salt and sesame oil.
Heat a wok or large heavy skillet over high heat until hot and add vegetable oil. Heat vegetable oil until hot but not smoking and stir-fry gingerroot and garlic 30 seconds. Add asparagus and stir-fry 30 seconds. Stir cornstarch mixture and add to asparagus. Bring liquid to a boil, stirring, and stir-fry mixture until asparagus is well coated. Sprinkle asparagus with sesame seeds and toss.
Serves 4 as an entree with rice or 6 as a side dish.