Add the red pepper flakes and onion to the pan and continue frying 2 to 3 minutes until the onions soften. Add the garlic, tomato paste and peppers and fry another 2 to 3 minutes until the tomato paste starts to caramelize. Stir in 3 cups of cold water and the maple syrup and reduce the heat to medium. Let the sauce simmer while you cook the noodles.