First wash and soak the rice in sufficient water for a minimum of 3 hrs. You can leave it to soak overnight as well.
Then transfer the rice to a mixie/blender, add sufficient water and grind it into a coarse batter. The batter should be slightly thin.
Now add the coconut, salt to the batter and pulse for a couple of times until everything is blended well. Keep it aside.
Now heat a pan with oil and add the mustard seeds. Once the mustard cracks, add the chana dal and broken urad dal. When the dal starts to turn golden brown, add the jeera, dry red chilli, curry leaves, asafoetida and continue to saute until the dals are golden brown.
Now, add the batter to the pan and stir continuously until the water evaporates from the batter and it comes to a ball consistency. Turn off the flame and let it slightly cool down until you will be able to handle it with your hands.
Once it is cool enough, make small sized balls. Steam the balls for 10 - 15 mins until they are cooked through.
Serve hot with tomato thokku or any spicy chutney.
While making the balls, roll them gently. If you roll the balls tightly, then the balls will turn out hard after steaming.
You can oil your palms if the batter is sticking while rolling the balls.
Do not over steam the balls, they would turn out hard.
The steaming time would depend on the size of the balls, stove settings and quality of rice. If you are unsure, after 10-12 mins of steaming, try breaking one of the balls and check if the center is cooked. If it is still not cooked, steam for a few more mins.