Wash and soak the rice overnight. Next morning, change the water couple of times, drain the rice. Grind the rice to almost smooth and coarse texture. Mostly, this can be sort of minute coarse rice grains.
Take water in a pan and bring to boil. When it is in the stage of rolling boil, add salt, cumin (if adding), slowly add the rice batter and keep stirring quickly to ensure it gets cooked. This takes about 10 - 15 mins to get cooked.
Have the sheets ready and when the mix is hot still, spread out as small discs and sun dry till done.