Prep the Chana: Boil water in a pot and add the fresh green chana. Cover and let them cook for about 10 minutes. Do not overcook; they should be slightly tender but hold their shape. Drain the water completely.
Crush the Chana: Once cooled, transfer the chana to a mortar and pestle or a mixer grinder. Crush them coarsely. Do not make a fine paste; you want chunks for texture.
Make the Paste: Crush the ginger, garlic, and green chillies together into a coarse paste.
Mix Ingredients: In a large mixing bowl, take the crushed chana. Add the chopped onion, ginger-garlic-chilli paste, turmeric, red chilli powder, cumin-coriander powder, hing, and sesame seeds.
Add Binding Flour: Add the Besan (Gram flour) and Rice flour to the bowl. The rice flour adds a great crunch to the chana vada.
Season and Bind: Add salt, chopped coriander, and the carom seeds (crush ajwain between your palms before adding). Mix everything well.
Form the Dough: The moisture from the chana and onion might be enough to bind the mixture. If it feels too dry, sprinkle a very small amount of water to form a tight dough.
Shape the Vadas: Grease your palms with a little oil. Take a small lemon-sized portion of the mixture and flatten it into a patty (vada) shape.
Fry: Heat oil in a deep pan. Once hot, lower the flame to medium. Gently slide the vadas into the oil.
Serve: Fry until they turn golden brown and crispy on both sides. Remove and drain on a tissue paper.