Wash the coriander leaves and spread it on a clean towel and allow to dry in shade. Then chop them into small pieces.
In a kadai put the oil and fry asafetida and urad dhal till it turns light brown. Then add tamarind and fry for a while. Then add red chillies and fry just for a second and remove. Then put the coriander leaves and fry for few seconds. Remove and cool it. First put the fried dhal/chilli/tamarind in a mixie along with salt and grind it to a coarse powder. Then add the coriander leaves and grind it two or three rounds without adding any water.
This can be taken with idli/dosa or with curd rice. Also it can be mixed with hot rice along with a teaspoon of ghee or gingelly oil.