Preheat the grill to medium-high heat. Spray the grill rack with cooking spray.
Brush 1 side of a tortilla with some melted butter. Place the tortilla on the grill, buttered-side down. Arrange the banana slices on the tortilla and top evenly with the chocolate morsels. Sprinkle with the brown sugar and cinnamon. Place the remaining tortilla on top to cover the bananas. Brush with more butter and sprinkle some brown sugar on top. Grill until the chocolate is melted and the bananas are soft, 3 to 4 minutes per side. Cut into wedges and serve with ice cream and caramel sauce, if desired. Serve immediately.