Soak the lentils with enough water at least for 3 hours. Chop all the greens very finely including green chillies.
Method
After soaking the lentils, it would have turned really soft. Drain off the water completely and using mixer grinder grind it to coarse paste.
In a wide bowl transfer the ground lentils. Throw in chopped dill leaves, coriander leaves, curry leaves, green chillies and salt. Mix everything very well.
Take lemon sized mixture in hand and shape it like a ball, then flatten using your fingers. Keep a batch of vadas ready.
Heat oil in a heavy bottom wok and when it's hot enough, drop 3 to 4 vada in it. Fry them till the color changes to little brown. Once done, using a slotted ladle remove them from oil.
Very delicious chana dal vada is ready to serve along with cup of hot tea.
Notes
Soak the lentils not less than 3 hours otherwise it will not grind perfectly.
Drain the water completely from the lentils, you can even spread them over cotton cloth to remove the extra moisture.
More moisture makes the vada turn soggy soon. So ensure it is drained and dry.
The vada tastes good when it is bit spicy. So use enough green chillies.
To check the oil temperature, drop a pinch of lentil mixture in to oil. If it raises to the top immediately, the oil temperature is perfect.