In a medium size bowl, combine black-eyed peas with 3 cups of water. Soak for at least 3~4 hours or overnight. When ready, the beans will have increased in volume and will be quite tender.
Drain the water thoroughly. Make sure that there is no excess water left in the beans, otherwise the batter might get too watery.
Add the soaked and well drained black eyed peas to a food processor or blender jar. Add green chilies, ginger, garlic, cilantro and salt. Grind to a coarse paste without adding any water. If the blade refuses to move, then add 1~2 tablespoons of water. The mixture should hold its shape when squeezed.
Heat oil for deep frying in a small wok or heavy bottomed pan on medium heat. To test the oil, add little batter to the hot oil and if it sizzles and comes to the surface, then it is ready. If it sinks to the bottom, heat the oil for a few more minutes.
Lightly wet your hands and take a small lime size portion of the batter. Pat it into a thick disc on the palm of your hand. Gently slide it into the hot oil, away from you.
Depending on the size of your pan, fry about 4~6 vadas at a time. Make sure not to crowd the pan. Fry on medium flame until vadas are golden brown on both sides. Remove with a slotted spoon onto a paper towel lined plate and repeat with the remaining batter.
Serve hot as is or with any chutney.