Soak tamarind in warm water for 5 minutes and use another cup of water to extract the juice. Set aside.
Add two cups of water and sprouts to a soup pot, bring to boil, simmer for 5-6 minutes.
Add the tomatoes, tamarind water, salt, turmeric, Rasam powder, and pepper cumin powder.
Bring to boil and simmer for 4-5 minutes, until the tomatoes are done. Remove from the flame.
Heat oil in a pan. Add the red chilies and mustard seeds, when it splutters add cumin, asafetida, and curry leaves. Fry for 30-40 seconds. Pour the tempering on to the rasam.
Garnish with cilantro. Serve with cooked grains and veggies.