Wash and soak chana dal for at least 2 hrs.
When ready to make the vadai, wash and clean the greens, pluck out the leaves and the tender leaves, once it drains well, then chop it finely.
Drain the chana dal, reserve 2 tbsp aside and in a mixer take the green chilies, red chili, ginger and grind to a coarse paste.
Transfer to a bowl, add pounded garlic, fennel leaves, finely chopped onions, chopped greens, coriander, curry leaves and add 2 tbsp chana dal.
Mix well and heat a Kadai with oil.
When the oil is hot, take a small ball of the paste, flatten it on your palm or a greased sheet, plate or whatever works out best.
Gently slide into hot oil and deep fry in batches until golden on all sides.
Drain on a kitchen towel and serve hot with chutney.