Wash sago, drain and keep aside for an hour. Boil water in a large pot.
When boiling hot, add sago, cumin seeds and salt while stirring continuously. Decrease the flame to medium and cook till the sago turns translucent. Turn off the flame immediately, mix in sesame seeds and cover. Do not cool the mixture for long as it tends to thicken. The texture should be like pouring custard consistency.
Place a clean plastic sheet under the sun. Bring the nearly hot mixture and start pouring a spoon full (1.5tbsp) onto the sheet making round vadiyalu /wafers. Dry them under hot sun for two to three days. Store in airtight container.
Deep fry the vadiyalu in hot oil. Serve as a snack or with curry, sambar or rasam.