Grind together small onion, garlic, cumin and 2 tbsp coconut with 1-2 tbsp water to a smooth paste. Add this ground coconut paste and salt to thick coconut milk, mix well.
Combine rice flour and grated coconut (1/2 - 3/4 cup). Just pulse it in food processor or mixie for a few seconds.
Dry roast the rice powder coconut mixture in a heavy bottom pan / vessel, on low flame for 8-10 mins. Add the coconut milk mixture to this gradually. Continue cooking on low flame for 2-3 mins.
Remove from fire and add boiling water to make a smooth dough. The dough should be soft and not sticky. Add sesame seeds to the dough and knead for 3-4 mins. Cover the dough with a damp cloth and set aside for half an hour.
Divide the dough into small portions, the size of a small lemon. Roll the dough into circles (refer notes). Wrap the rolled-out dough around a greased rod or you can use a wooden rolling pin. Press the overlapping edges together to form a small curl.
Slide it off the rod. Repeat till all the dough is used up. Cover the shaped rolls with damp cloth to prevent it from drying out.
Heat oil in a deep pan. Make sure the oil is hot, but not smoking hot. Add the shaped rolls and fry it till it turns golden or darker shade of brown. Cool and store in airtight containers.
You will get 25-30, small-medium size Kuzhalappam with the above qty.