Heat a kadhai or a Dutch oven over medium heat. Add the peanuts to it. Roast the peanuts in the oil by moving them around every now and then, till the skin turns color but does not burn. This should take about 7-8 minutes. Remove the peanuts from the pan and let them cool on a plate.
Heat the oil over medium high heat in the same pan. Add the mustard seeds to it. Once they splutter, add the chana dal, curry leaves, dried red chillies and Thai green chillies. Give it a quick toss till the chana dal starts to turn darker.
Add the turmeric powder and remove the pan from heat. Mix the turmeric well to the rest of the ingredients. Add the precooked or leftover rice to this and mix gently, so as not to break the rice.
Add salt, lemon juice and lemon zest. Mix well gently.
Top with the roasted peanuts and some minced cilantro.
Notes
Make sure the rice is at room temperature before you add it to the seasonings and mix. This will cause less breakage to the rice as you mix it.
Add the lemon juice and zest to room temperature rice. This minimizes loss of Vitamin C from the lemon and also helps the rice from becoming bitter.
You can use just the lemon juice and skip the zest, if that is more convenient.
You can skip the peanuts to make it nut free.
You can skip the chillies or reduce the quantity to make it less spicy.