Wash the chana dal several times with water until it is clear. Then soak the dal in water for 2 hours and then drain the water completely from the dal - there shouldn't be any water in the dal.
Add green chillies, dry red chillies, garlic and ginger to a blender. Then, take 2 tablespoons of the soaked dal and keep it aside. Now add the remaining dal to the blender and grind it into a coarse mixture.
Transfer the mixture into a bowl; add chopped onion, salt, cumin seeds, coriander leaves, curry leaves and the remaining soaked dal which we kept aside before.
Mix together all ingredients into a binding mixture. To check, take a small portion of the mixture and make a vada. The mixture should hold its shape and should not fall apart.
Divide the mixture into equal portions and take a small portion into your palm to press it slightly to form a disc shape. Heat a frying pan with enough oil for deep frying the fritters
Drop the fritters carefully into the oil and fry on a medium flame for 2-3 minutes, turning both sides or until they turn into golden brown colour.
Transfer the cooked fritters onto a kitchen towel to absorb excess oil. Serve them hot with chutney or tomato kethup.