If using toor dal, then soak them in water for about 30 minutes. This will reduce the cooking time significantly. There is no need to soak, if using red lentils.
In a medium size saucepan, combine 2 cups of water and the dal. Bring to a boil on medium heat, lower the heat and simmer till the lentils are tender, but not mushy. Take about 15~20 minutes for masoor dal and 25~30 minutes for toor dal. Drain and set the cooked lentils aside until ready to use. Reserve the cooking liquid to use as stock in soups or pulusu.
In the same medium size saucepan, bring the remaining 1 cup of water to a boil. Add salt to taste. Slowly stir in thelaga pindi and mix well until cooked through. It takes about 3~4 minutes to absorb all the water and get thick. Take the saucepan off the heat and keep aside.
Heat oil in a nonstick pan on medium heat, add chana dal, urad dal, cumin & mustard seeds and dry red chilies. Once the seeds start to splutter, add green chilies and curry leaves, cook for 1 minute. Then add the cooked lentils and thelaga pindi mixture. Mix well and season with salt. Cook for 4-5 minutes, stirring occasionally until the mixture dries up and cooked through. Serve with steamed rice.