1. Rinse and sort the mung beans or lentils discarding any that are discolored, as well as foreign items. Put them into the water with the chiles, turmeric, and salt and bring to a boil.
2. Reduce heat and simmer, stirring often for 30 minutes. Dal should be thick, but it may be necessary to add water (1/2 cup at a time) during cooking.
3. After the beans are cooked (consistency will be like mashed potatoes), continue simmering over very low heat while you heat the oil, browning the mustard seeds, and garlic. Mustard seeds act quite a bit like popcorn when heated, so be prepared for them to leap out of the pan.
4. Remove the chiles and add the oil mixture to the beans. Turn off the heat. Add in the curry powder and lemon juice and taste to adjust spices if needed. Serve with bread (whole wheat tortillas are a nice choice), dosas, or rice and enjoy!