Cover the chickpeas with water in a large bowl. Set aside at room temperature to soak for at least 12 and up to 24 hours. They will end up doubling in size.
Drain the chickpeas. Rinse and dry them as thoroughly as possible.
Place the chickpeas and salt in the bowl of a food processor. Pulse to create fine crumbles. Add the cilantro, parsley, onion, garlic, salt, cumin, coriander, crushed red pepper and black pepper. Blend until the mixture turns into a thick green paste, scraping down the sides as needed. Remove the blade from the bowl, then cover the bowl of the food processor and refrigerate for 1 hour to let the batter set.
Remove the falafel batter from the fridge. Sprinkle the baking powder over the top, then gently fold it throughout.
Line a baking sheet with parchment paper. Set aside.
Using a medium spring-loaded cookie scoop (or your hands), scoop, firmly pack, and roll about 1 ½ tablespoons of batter into a round ball and add it to the parchment-lined baking sheet. Repeat with the remaining batter.
Heat the air fryer to 400ºF. Arrange about 12 falafel balls in the air fryer basket, spray the falafel balls with cooking spray, and cook for 10 minutes, until golden brown and puffed. Repeat with the remaining falafel balls to make about 36.
Transfer the falafel to a serving platter and serve tahini sauce for dipping.