Heat oil in a non stick wok. Place prawns in a bowl, sprinkle salt and 2 tsps lemon juice over them. Crush Sichuan peppers and add along with crushed peppercorns and mix well. Add to the wok.
Add ginger paste, garlic paste, lemon rind, five spice powder and mix. Add tamarind pulp and grated jaggery and mix. Adjust salt and cook till the prawns are done. Do not overcook the prawns.
Transfer only the prawns into a serving bowl. Thicken the marinade remaining in the wok. Add salt and remaining lemon juice to thin strips of ginger.
Pour the thickened sauce over the prawns, garnish with the pickled ginger strips and serve hot.