01 - Drain and rinse soaked chickpeas thoroughly, then pat dry.
02 - Combine chickpeas, onion, garlic, parsley, cilantro, cumin, coriander, cayenne pepper, salt, and black pepper in a food processor. Pulse until the mixture resembles coarse sand and holds together when squeezed; avoid over-processing.
03 - Transfer the mixture to a bowl, then gently stir in baking powder and flour until just combined. Cover and refrigerate for at least 30 minutes to firm up.
04 - Pour vegetable oil into a deep skillet or saucepan to a depth of 2 inches and heat to 350°F.
05 - With wet hands or a falafel scoop, shape the mixture into balls or small patties approximately 1 1/2 inches in diameter.
06 - Cook falafel in batches, turning occasionally, until deep golden and crisp, about 3 to 4 minutes per batch. Drain on paper towels.
07 - Whisk tahini, cold water, lemon juice, minced garlic, and salt until smooth and creamy. Adjust water for desired consistency.
08 - Serve falafel hot, drizzled with tahini sauce, accompanied by pita bread and optional vegetables or pickles.