Heat water to boil. Pour 2 tsp sesame oil in it and add rice flour with constant stirring so that it becomes thick. Cover and keep aside for 1/2 hour.To this flour, add red chillie powder, salt and asafoetida and knead well. Make very small balls of this and steam it on a plate inside the idli cooker. In 1 tsp oil, add mustard seeds. When it bursts, add these ball and fry well.