Combine pizza sauce ingredients in a small saucepan and bring to a boil, simmer for about 5 minutes.
Meanwhile, sauté peppers and onions in a large nonstick skillet in oil, stirring frequently, until tender (about 3 to 4 minutes). Reduce heat to medium-low.
Add cooked meatballs and pizza sauce. Cover and cook, stirring occasionally, until heated through, 5 to 6 minutes.
Divide among rolls and sprinkle with cheese.
Notes
If needed, you can substitute a jar of prepared pizza sauce (or our Crockpot Marinara Sauce) and purchased frozen meatballs.