Rinse and soak Chana for about 1-2 hours. Rinse and strain again and place in large pot. Add water and bring to boil.
Add ginger, chilis, and turmeric. Lower heat and simmer for 40-50 minutes until chana beans are soft.
In a small saucepan, heat ghee. Stirring constantly, add cumin seed, mustard seed, and brown momentarily until seeds sputter a little, then add asafetida.
Stir in chopped onion until lightly brown.
Add tomato, stirring to capture all the spices and pour into Dahl.