In a small mixing bowl, combine tomato sauce ingredients, mix well and set aside.
In a large mixing bowl, combine meatball ingredients and mix thoroughly. Divide mixture into approximately 14-16 1.5 ounce meatballs.
Layer meatballs into a slow cooker that has been coated with olive oil cooking spray. Cook meatballs on high for 2 hours. After two hours, top meatballs with the tomato sauce mixture, but do not stir. Cook on high for an hour.
Open the slow cooker, and gently stir the meatballs. Cook for one additional hour.
When ready to eat, open remaining sub buns and place on a clean baking sheet. Layer each open-face sub bun with 2 slices of provolone cheese and place in the oven for remaining 2-3 minutes of cook time. Remove meatballs and sub buns from oven when thoroughly cooked and cheese is melted.
Serve approximately three meatballs per sub bun with the desired amount of tomato sauce and enjoy your Meatball Hero.