Rinse and pick over the dried chickpeas, removing any debris, discolored or misshapen beans in the process. Place the chickpeas in a bowl and cover with at least 2 inches of cool water. Place the bowl, covered, in the refrigerator for at least 12 hours and up to 24 hours.
Drain the chickpeas and place in the work bowl of a food processor fitted with a blade. Add the onions, parsley, cilantro, garlic, cumin, salt and cayenne to the work bowl, fix the cover in place and pulse until everything is finely ground but not pasty. Sprinkle the baking soda and 8 tablespoons of the flour flour over the ground chickpea mixture and pulse again until it is evenly combined. Scrape the falafel mixture into a mixing bowl. Use your hands to mix in the remaining flour until the mixture does not stick to you as much. Cover and refrigerate for at least 2 hours before cooking.
Line a plate with paper towels and set aside.
Heat about 3/4 of an inch of oil to about 375°F in a high-sided, heavy-bottomed pan. While oil is heating, form the falafel mixture into ping pong size balls, using about 1-1/2 Tablespoons at a time. You can fry like this or flatten into patties.
When oil reaches the right temperature, drop about 6 balls in at a time. Fry for about 1 minute, flip the balls and fry for an additional minute. Use a slotted spoon or tongs to transfer the falafel to the lined plate.
Serve hot with a side of tahini sauce or stuffed into pita halves with chopped tomatoes, onion and tahini sauce.
Get 'em while they're hot, boys!