In a large pan, add washed moong dal, green chilies, chopped onion and tomato, turmeric power and sufficient water. Cook until the dal is cooked. (Or alternatively you can use pressure cooker till 2 or 3 whistles)
Now add the red chilli power and required salt, bring it to boil.
Lower the flame and add tamarind paste and jaggery. Cook until raw smell of tamarind goes away and till you reach desired consistency. You can add or reduce water to your desired consistency. Switch off the stove and garnish with coriander leaves.
Heat a small kadai with oil, add the mustard seeds till they splutter, and then the cumin seeds, red chili, curry leaves and asafoetida. Pour this tadka over the dal, and mix well and serve with hot.