In a bowl, combine the shrimp, chili, curry and turmeric powders, ginger and garlic. Set aside for 5 minutes to marinate.
Heat the oil in a wok or skillet and stir-fry the mustard and cumin seeds over medium heat until aromatic, about 5 minutes. Add the onion and curry leaves and stir-fry until the onion is golden brown, about 4 minutes. Add the shrimp and stir