Defrost shrimps; rinse with cold water and pat dry thoroughly with paper towels.
Marinate in the marinade ingredients.
Nip off the ends of the snow peas, then parboil and set aside.
Mix the combined sauce ingredients.
Heat 1 Tbs oil in wok, stir fry the snow peas for a few seconds, add a sprinkling of salt.
Mix well; remove and place in the center of a serving platter.
Heat 8 Tbs oil in wok.
Stir fry the marinated shrimps for 15 to 20 seconds until the shrimps change color.
Remove shrimps with a strainer; drain oil from wok.
Pour 1 Tbs of the used oil into wok.
Saute the scallions and ginger slices for a few seconds.
Add shrimps and stir quickly.
Pour in the combined seasoning sauce.
Mix thoroughly and remove half of the shrimp and put them on one side of the platter.
Add 3 Tbs catsup to the shrimp in the wok and stir for a few seconds.
Remove and put on the other side of the platter.