Soak the lentils in half a cup of water for half an hour. Then drain the water and keep the lentils ready for cooking.
Heat the oil in a pan and add the mustard seeds. When the seeds splutter, add the red chillies (each broken in half) and sautxe9 a couple of times. Add the asafetida powder and stir a couple of times, making sure it doesn't burn.
Now add the chopped beans and the lentils and about 1/2 a cup of water. Add the salt and turmeric powder, stir well and bring to a boil. Turn the heat down and let the beans and lentils cook till done but not mushy, and there is no water left in the pan.
Another way of cooking ( a faster method) this step of the procedure is to microwave the French beans and the soaked and drained lentils with a couple of tbsps of water till done. I do this at 100% for 8 to 10 minutes.
Add this to the pan after adding the asafetida powder and stir well.
Take the pan off the heat and add the coconut. Stir to mix well and serve warm with rice and a gravy-based "curry" like sambhar, rasam or pulissery.