Soak rice and chana dal for 1 hour and cook it with salt, turmeric powder and 2 tsp oil with adequate water (enough to cook the rice grain, but not to make it very soggy)
Heat remaining oil in a pan. Add mustard seeds, cumin seeds, curry leaves, urad dal and hing. When urad dal gets light pink, add rice and dal mixture, salt, red chilli powder, chaat masala and mix properly.
Add peanuts and lemon zest and mix well. Allow it to cool to room temperature.
Add lemon juice and coriander leaves and mix softly.