Wash string beans. Cut off ends and string. Cut into 1-1/2" pieces.
Dry on paper towel.
Heat oil until smoking hot; slide in string beans gently. Deep fry
beans until wrinkled, about 5 minutes. Turn frequently. Drain. Remove.
Reheat 2 tb oil in wok. Stir-fry ginger for 10 seconds. Add pork.
Stir-fry until color changes. Add preserved vegetable. Add beans,
salt, soy sauce, sugar, and stock. Stir-fry 2 minutes or until dry.
Add last 3 ingredients. Stir-fry for 1 minute or until thoroughly
heated.
Serve hot or cold.
You can find the preserved vegetables in the canned food section of
most Asian groceries. I find that stir frying the string beans in a
little bit of oil works as well as deep frying them in 2 cups of oil.