Heat water and salt in a vessel. When it boils, put the rice flour and make a hole in the centre. Close the vessel tightly with a lid, simmer the flame and keep it for 1 minute. Open the lid and with the tip of a spoon mix the flour. Remove the vessel from fire and allow the content to cool. Knead it to a fine dough without adding water. Take small balls from the dough and roll each of it into thin, round shapes by spreading rice flour over the balls.
Heat a thick bottom flat pan. Cook the pattiri by turning both side till done. Don't use any oil while cooking.
Grate the coconut. Add some water and take thick milk from it. Soak the pattiri in this milk just before serving.