Soak Urad dal in sufficient water overnight. Next morning, grind to a coarse paste in the food processor with salt and just a bit of fresh water. I had freshly ground ginger paste which I used, otherwise, you can grind the ginger and chillies with the dal. I added green chilli paste, ginger paste, hing to the mixture. I also added (optional) whole cumin seeds + fennel seeds + lightly crushed whole dhania seeds. Beat the mixture with your hands to make a light batter. Heat oil in a kadai and fry vadas tilll golden brown. Add them to warm water, press with hands to remove the water and set aside. Beat yogurt with water and salt and spread over the wet wadas. Garnish with red and green chutneys, red chilli poweder, roasted cumin powder, chat masala (optional. I didn't use it this time), and cilantro. Serve chilled.