Wash and soak the whole moong dal in a lot of water for 6 hours.
Drain the water. Grind the soaked beans, green chillies, salt and ginger into a little coarse or smooth paste. Use very little water if needed.
Heat oil in a pan for deep frying.
Wet your hands and take a lemon sized ball of batter and flatten it on your palm or on a plastic sheet. Make a small hole in the middle of the vada so that it cooks evenly all over.
Slowly drop it into the hot oil. Fry it on both sides on medium flame til golden brown color.
Remove them from oil and serve hot with any chutney.