Rinse and drain chickpeas. Add them to a large mixing bowl and smash up the chickpeas with a fork or potato masher, leaving some of the chickpeas whole for texture. You can also pulse them in a food processor. Just be sure not to blend too much.
Add the tahini, Dijon mustard, and maple syrup to a medium bowl and whisk until combined. Pour the dressing over the chickpeas, then add the green onion, celery, and sweet relish to the chickpea mixture. Stir everything together until well combined.
Set out two bread slices. Spread ½ cup of the chickpea salad onto one slice of bread. Add lettuce, a couple of tomato slices, and red onion to the other piece.
Put them together, make a sandwich, and enjoy.
