In a bowl, mix 250 grams of rice flour with a pinch of salt. Gradually add 250 ml of boiling water to the rice flour, stirring continuously to form a smooth dough. Let the dough cool for a few minutes until it is comfortable to handle.
Grease an idli steamer or idiyappam steamer with a little oil to prevent sticking.
Fill an idiyappam press or a murukku press with the prepared dough. Press the dough through the idiyappam press onto the greased steamer plates, forming thin, circular strings.
Steam the idiyappam for 7-10 minutes on medium heat until they are cooked and soft. Remove the idiyappam from the steamer and let them cool for a couple of minutes before serving.