Add the chickpeas, onion, garlic, parsley, cilantro, cumin, coriander, salt, and pepper to a food processor. Pulse until the mixture is finely chopped but still has some texture.
Transfer the mixture to a bowl and stir in the flour and baking powder until evenly combined. Let it rest for 5 minutes.
Scoop out about 2 tablespoons of the mixture at a time and shape into small patties. Brush both sides lightly with olive oil.
Place the patties in a single layer in the air fryer basket. Cook at 375°F for 12 to 15 minutes, flipping halfway through, until golden and crisp.
While the falafel cook, make the dressing by whisking the tahini, lemon juice, and water together until smooth.
Assemble the bowls by dividing the romaine, tomatoes, cucumber, feta, and olives among four bowls. Top each with several warm falafel patties and drizzle with tahini dressing.