Drain and rinse the soaked chickpeas. In a food processor, combine chickpeas, onion, garlic, parsley, cilantro, cumin, coriander, baking powder, and salt. Pulse until a coarse mixture forms.

Form the mixture into small balls or patties.

Heat oil in a frying pan over medium heat. Fry the falafel until golden brown on all sides, about 3-4 minutes per side. Drain on paper towels.

In a mixing bowl, whisk together tahini, water, lemon juice, garlic, and salt until smooth. Adjust water for desired consistency.

Warm the pita bread in a dry pan or oven. Fill each pita with lettuce, tomato, cucumber, red onion, and several falafel balls.

Drizzle with tahini sauce and serve immediately.