Clean and string the beans and cut them into equal a size. Heat oil in a kadai, add mustard seeds and let it splutter. Add channa dal, urad dal, red chillies and asafoetida powder and fry them. Next add the cut beans and salt. Sprinkle some water and keep tossing the vegetables. When the beans get cooked and become soft & dry add the grated coconut, sprinkle some sugar, mix them well and remove. Sugar is added to enhance the taste.