01 - Drain and rinse the soaked chickpeas, then pat them dry thoroughly.
02 - Combine chickpeas, onion, garlic, parsley, cilantro, cumin, coriander, cayenne, salt, and pepper in a food processor. Pulse until the mixture resembles coarse sand and holds together when squeezed, avoiding over-processing.
03 - Transfer the mixture to a bowl, then stir in the baking powder and flour until just combined. Cover and refrigerate for at least 30 minutes.
04 - Heat 2 inches of vegetable oil in a deep skillet or saucepan to 350°F (175°C).
05 - With wet hands or using a falafel scoop, form the mixture into balls or small patties about 1.5 inches wide.
06 - Fry falafel in batches, turning occasionally, until deep golden and crisp, approximately 3 to 4 minutes per batch. Drain on paper towels.
07 - Whisk tahini, cold water, lemon juice, minced garlic, and salt together until smooth and creamy, adjusting water to reach desired consistency.
08 - Serve falafel hot, drizzled with tahini sauce, accompanied by pita and assorted vegetables as desired.