Soak idli rice along with red chilli for 3 hrs minimum. Drain water and grind it in a wet grinder with very little water, just enough for the grinder to run freely. The batter should be thick as well as smooth. It will take a bit of time, but do make sure to grind smoothly. Sprinkle water in between if its too tight.
Meanwhile, powder fried gram dal (pottukadalai) to a fine powder in a mixie.
Sieve it well and measure 1/2 cup heaped flour. Transfer the ground wet batter to a mixing bowl.
Add sesame seeds, ajwain, asafoetida and required salt, along with fried gram dal flour. Add hot oil. Heat oil side by side for deep frying.
Mix well and make a dough that is non-sticky. You can add one or two more tbsp of fried gram dal flour. But not more than that. *Refer notes. Place the murukku plate in the murukku press.
Fill the press with the dough and squeeze in flat greased ladles into round murukkus. Do not layer it too much as it will take time to get cooked.
Drop the murukkus gently into hot oil and cook until the bubbles ceases. Flip and cook until golden and shhhh sound ceases.
Drain in paper towel. Repeat to finish the batter.