Drain and rinse the soaked chickpeas. Place them in a food processor with onion, garlic, parsley, 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.

In a mixing bowl, combine tahini, water, lemon juice, minced garlic, and salt. Whisk until smooth and adjust water for desired consistency.

Warm the pita bread in a dry pan or microwave. Cut open the pita and stuff it with lettuce, tomato, cucumber, and several falafel balls.

Drizzle tahini sauce over the filled pita and serve immediately.