Preparation:

Pulse chickpeas, flour, and garlic in food processor until smooth (about 20 seconds). Remove chickpea mixture and shape into patties, each roughly ½-inch thick and 3 inches in diameter. 

Heat canola oil in skillet over medium-high heat. Add patties, sautéing about 3 to 4 minutes on each side, or until brown and crispy (can be done in batches). Chickpea mixture will make roughly 16 falafel patties. Reduce heat to low. 

Whisk together water and tahini until mixture becomes thick and fluffy, but still liquid (additional water can be added as desired). 

Split each pita in half and stuff with half romaine leaf. Add 2 falafel patties to each ½ pita and top with tomatoes. Drizzle 1 tbsp tahini over each pita half and serve.