Place dried chickpeas in a bowl, cover with cold water and soak for at least 15 hours.
Then drain the chickpeas and place them in a food processor with the scallions, garlic, parsley, mint, chili, salt, cumin, and coriander.
Mix baking powder with the warm water and add mixture to food processor. Process until smooth. Transfer mixture into a small bowl, cover, and refrigerate for 30 minutes.
Meanwhile, heat about 2 inches of oil in a heavy pan to 375 degrees F.
When falafel mixture is chilled, roll into golf-sized balls. Carefully place a few at a time into the hot oil, making sure they do not stick to the bottom. Cook, turning, for about 6 minutes, or until the balls are a dark, even brown on all sides. Remove with slotted spoon and drain on paper towels.
Serve either in sandwiches or as a falafel first course.