Combine all the dals and pressure cook until very soft.
Heat 2tbsp oil in a medium saucepan, add the red chilies, cumin seeds, mustard seeds and fenugreek seeds. Once the seeds start to splutter, add the curry leaves and asafoetida.
Next add the green chilies, onions and radish. Cover and cook till the veggies are tender, about 5~6 minutes.
Next add the tomatoes, chili powder (if using), turmeric, sambar powder and salt. Cook covered until tomatoes turn mushy.
Add tamarind pulp and cooked dal. Mix well and add enough water to get the desired consistency. Simmer for 5~6 minutes. Turn off the heat and garnish with chopped cilantro. Serve with steamed rice.