Wash and soak the Mung Dal for an hour. Drain and wash again. In a deep pan, add the drained dal and 3 cups water, salt and turmeric. Cover and cook on low-medium heat until dal mashes easily. 20-25 minutes. Or pressure cook on medium for 1 whistle. Let the pressure release on its own as it cools slightly. The dal in the pictures is pressure cooked hence well mashed. Once the beans are cooked, In a small(tiny) pan, add the oil and heat on medium-high heat. Add mustard seeds and let them start to sputter. Add the garlic, chili and asafetida-hing. Cook until the garlic and chili have brown edges. Drop this tadka into the cooked dal, mix lightly, and serve hot.