In a bowl, mix together the rice flour,self raising flour, salt and chilli powder.
Add a drop of water to the above ingredients and make it to a consistency of a batter which is neither too loose nor too thick.
Heat the oil on a medium flame.
Coat the prawns with the batter and deep fry in the oil until brown and put them aside.
In another pan, heat 1 tsp oil add the green chilli, ginger and garlic then fry for a minute.
Add the sliced onions and fry until translucent. Add the deep fried prawns and toss.
Serve hot.