Soak Chana Dal/Split Bengal gram lentil, for at least 3-4 hrs.
If using frozen corn, thaw it and soak in water for few minutes.
Drain water from chana dal, add all the ingredients in grinder and grind to a coarse paste.
Transfer the paste in a bowl and add rice flour to it.
Give shape like vada , flatten with a hand a little. You can shape it like doughnut with a hole in center.
Fry in medium hot oil, till light brown. Do not fry in very hot oil, as vadas with be cooked from outside but will remain raw from inside.
Serve with chutneys or ketchup of your choice