Wash the moth beans well and soak it in plenty of water for 6 hours.
Drain all the water and keep covered with a fitting lid or keep in a box on the counter overnight, for sprouting. If required you can sprout for 24 hours to get longer sprouts. If sprouting for more than 12 hours, make sure you rinse the beans once midway so that it doesn't get slimy. After rinsing, drain and keep in the closed box. Once the beans have sprouted, store in airtight container in the fridge for 1-2 days maximum or use it right away.
Cooking the matki / moth beans: Rinse the sprouts with water and drain. In a pressure cooker, place the sprouted matki with 2 cups of water, 1/4 tsp turmeric and 1/2 tsp oil. Pressure cook for 1 whistle and then reduce the flame to sim. Allow to pressure cook on sim for 5 minutes. Switch off the cooker and allow to cool. If you don't have a pressure cooker, these can be cooked in a large pan on the stove top, uncovered, for 15 mins or so until tender.
Finely chop the onion and tomatoes.
In a heavy bottomed pan, heat the oil. Add the asafoetida, cumin seeds, mustard seeds, curry leaves, dried red chillies and stir until the seeds pop.
Add the finely chopped onion, grated ginger and garlic and stir well. On a medium flame, cook this for 5 minutes with constant stirring. Add the chopped tomatoes and salt. Stir this mix until the tomatoes are mashed to a pulp.
Add the coriander powder, garam masala, red chilli powder and keep stirring till you get a glistening curry paste.
To this paste, add the cooked moth beans along with the cooking liquid and bring to a simmer. Check for salt. Allow this curry to simmer for 5 minutes or so. It should not turn completely dry (see pics).
Remove into a serving bowl. Garnish with coriander leaves and a couple of red chillies.