Rinse and soak whole moong dhall and rice in water for 4 hours. Grind the above with green chilles, red chillies, ginger, cumin seeds, salt and little onion. Fry the remaining onions in oil and keep them aside. Make the peserat like dosas, and put a spoon full of onions on the dosa and fold the dosa before serving. Serve with corriander chutney or onion chutney.