preheat the oven to 400°
mix the tomato sauce with the Italian seasoning, garlic powder, onion powder, salt, sugar, red pepper flakes (optional) and water together in a small sauce pan
place the saucepan over low heat
add the meatballs to the pan, stir to combine
cover and cook on low for 10-15 minutes or until the meatballs are hot through, don't let them burn, stir as needed
open the sandwich rolls slightly and place them on the baking sheet
toast them lightly in the preheated oven
when toasty sprinkle a pinch of the shredded mozzarella in each roll and toast again just until melted
when the meatballs are hot turn off the heat
place 5 meatballs in each sub-roll
spread the extra sauce on top of the meatballs
sprinkle with the remaining mozzarella cheese
toast in the oven until melted
sprinkle each with a pinch of parmesan
serve hot