Wash 1 cup red lentils in several changes of water. Combine with 1 cup water and bring to boil over medium high heat. When boiling, add 2 medium peeled tomatoes, 1/2 tsp. turmeric and 1/4 tsp. cayenne pepper, reduce heat to low and cook covered for 20-30 minutes. Check to see if the lentils and tomatoes have softened. If so, mash well with a slotted spoon, add salt and cover to cook again. At this point, you can also add some more water (1/2 cup) to thin out if needed (end consistency should be between stew and soup but not runny). Keep mashing frequently to ensure all the ingredients are well blended. Once done, remove from heat and allow to cool slightly. In a separate heated pan, add 2 tbsp. oil, 1/2 tsp. cumin seeds and 1/2 tsp. mustard seeds and allow to sizzle for 10 seconds. Then add 2 thinly sliced garlic cloves, 3-4 curry leaves and 3 dried red chillies (split in half) and cook till then garlic starts to brown. Pour this oil mixture over the daal and cover quickly to let it smoke and flavor. Mix well and serve with steamed rice and achaar.