Break the heads of lettuce apart and use the smaller leaves to act as cups for the falafel. Reserve the larger leaves for other use. Cover the lettuce cups with a damp paper towel and refrigerate.
Put the chickpeas, garlic, onion, parsley, salt, cumin, red pepper flakes, mint, tahini and lemon juice into the bowl of a food processor and pulse until it forms a rough paste. Add the baking powder and flour and pulse until well combined.
Pour the oil into a skillet and place over medium high-heat for 2 to 3 minutes. Carefully drop the falafel into the hot oil by the heaping tablespoonful, in batches. Fry until golden, about 1 1/2 to 2 minutes. Flip and repeat on the other side. Remove to a paper towel lined dish. Repeat with the remaining falafel. Keep warm in a low oven until ready to serve.
Garlic Tahini Sauce:
Put the tahini, garlic, honey, water, soy sauce and lemon juice into a bowl and whisk until smooth. Stir in the chopped parsley, mint and salt and refrigerate until ready to use. Bring back to room temperature before serving.