Submerge the chickpeas in ample water within a medium-sized bowl and allow them to soak at room temperature for a minimum of 12 hours or up to 24, during which they will expand significantly. Thoroughly drain and rinse the chickpeas, ensuring maximum dryness; a salad spinner proves useful for this step.

Transfer the chickpeas and salt into a food processor bowl and pulse until the mixture reaches a coarse, granular consistency. Introduce the parsley, cilantro, onion, garlic, cumin, coriander, and black pepper. Continue blending until a dense, cohesive paste forms, pausing occasionally to scrape down the sides. Detach the blade, cover the bowl, and refrigerate the mixture for one hour to allow the batter to firm.

Retrieve the batter from the refrigerator, sprinkle the baking powder over the surface, and fold it in gently until uniformly distributed.

Prepare one baking sheet with parchment paper and another with a double layer of paper towels.

Using a medium spring-loaded scoop or your hands, form approximately 1½ tablespoons of mixture into compact balls and arrange them on the parchment-lined sheet. Repeat the process until all batter is shaped; the falafel may feel slightly loose but will hold together upon frying.

Pour one inch of oil into a large, deep-sided skillet and heat over medium flame. When a small bit of batter sizzles upon contact with the oil, carefully lower 10–12 falafel balls into the pan without overcrowding. Fry for 3 to 3½ minutes on each side, or until deep golden and crisp. Remove with a slotted spoon and drain on the prepared paper-towel-lined sheet. Repeat with remaining falafel.

Arrange the cooked falafel on a serving dish and accompany with tahini sauce. Serve while warm.