Put 1 cup dried chickpeas and 6 cups cool water in a large bowl, cover, and refrigerate for 12–24 hours until the chickpeas have expanded and softened.

Drain and rinse the soaked chickpeas. Dry thoroughly. Pulse in a food processor with parsley, cilantro, onion, garlic, cumin, coriander, salt, and pepper until finely textured and the mixture holds together when firmly pressed. Scrape down as needed; do not puree to hummus.

Whisk tahini with lemon juice and the 1/4 cup cold water until smooth. Chop the tomato and cucumber and shred the lettuce. Keep sauce and vegetables chilled while cooking.

Divide all the falafel mixture between 4 pitas, pressing a firm even layer no thicker than 1/4 inch across one side of each pita. Use the whole thin pita, without opening its pocket.

Heat the skillet over medium heat with 1/2 tablespoon oil per pita. Cook one pita at a time, falafel-side down, for 5–7 minutes until well browned. Flip and warm the bread side for about 1 minute. Check that the thin chickpea layer is cooked through and tender, with no raw or chalky center; lower the heat and extend cooking if needed. Repeat, using the remaining oil.

Divide the lettuce, tomato, cucumber, and tahini sauce between the 4 warm pitas. Fold gently and eat immediately for the crispest crust.