To make the pesto combine all ingredients in a food processor and process until smooth. Set aside.
Melt the butter in a medium skillet over medium heat. Once it has melted add in the garlic and cook for 30 seconds. Dip the inside of the sandwich thin roll into the garlic butter and then allow it to cook for 2-3 minutes to lightly toast the inside. Remove and set on a plate.
Spread the pesto on one half of the sandwich thin. On the other half place the mozzarella slices, roasted red peppers, and arugula. Top with the sandwich thin half that has the pesto on it and slice in half.