Heat olive oil in a wok or kadhai (deep vessel) and add mustard seeds and whole red chilies. Once mustard seeds start to splutter, add urad dal, chana dal and curry leaves. Reduce the flame to slow and lightly roast the dals for a minute till they become golden.
Add sliced onions and cook for 3-4 minutes till they become translucent, but are still crunchy. Add the raw mango and spices. Cook for another 2 minutes, and add the brown rice and salt.
Toss the whole thing around till the spices are mixed properly and cover and cook for 3-4 minutes to let the flavors permeate. Adjust spices if required and enjoy with some fresh curd.
Notes
You can use regular white rice or basmati but I love the texture that brown rice adds to this dishFeel free to increase the quantity of raw mango if this is not tangy enough for you