Place 2 tortillas on the grill over high heat. Top each with half the chocolate chips, half the marshmallows, and a sprinkle of cinnamon. Place the remaining two tortillas on top. Cook for 3-4 minutes, until the bottom tortilla is lightly browned and crisp. Carefully flip the tortillas. Cook for 3-4 minutes more, until the second side is lightly browned and crisp. Cut each into quarters and serve.