Step 1Preheat oven to 350 degrees F. Line a baking sheet with foil; coat with cooking spray.
Step 2Pulse chickpeas, parsley, cilantro, grated onion, panko, tahini, lemon zest, 1 tablespoon lemon juice, cumin, salt and garlic in a food processor until a coarse meal forms, 10 to 12 pulses, stopping to scrape down the sides as needed. Shape the mixture into 4 (1/2-inch-thick) patties (about 1/2 cup each). Arrange the patties on the prepared baking sheet; coat tops with cooking spray. Bake for 10 minutes. Flip the patties; coat tops with cooking spray. Continue baking until golden brown, 10 to 12 minutes.
Step 3Meanwhile, combine sliced onion, cucumber, oil and the remaining 1 tablespoon lemon juice in a medium bowl. Let stand at room temperature, stirring occasionally, for about 20 minutes.
Step 4Remove the patties from the oven; let cool for 5 minutes. Cut in half.
Step 5Meanwhile, place wraps directly on oven racks; bake until just warmed through, about 1 minute.
Step 6Add arugula to the cucumber mixture; toss to combine. Place the warmed wraps on a work surface; top evenly with the arugula mixture, falafel halves, tomato slices and tahini sauce. Working with 1 wrap at a time, fold 1 side of the wrap over the center and roll up burrito-style. Wrap the bottom half with foil to hold the wrap together.