Once the grill is up to temperature remove the cooking grid and carefully set aside (remember it is hot).
Add the olive oil and chopped onions to the dutch oven and allow to sweat 5-7 minutes.
Add the garlic to the onions and cook for an additional minute until the garlic becomes aromatic.
Add the cans of tomato sauce to the onions and garlic and mix to incorporate.
Replace the grid over the dutch oven ensuring the grid doesn't impede the grill's ability to close.
Place the meatballs on the grid in a strategic fashion ensuring that the meatballs are placed over the tomato sauce and are not touching each other. This will allow airflow and smoke around the meatballs and ensure even cooking time and smoke incorporation.
close the lid and allow the meatballs to smoke until they have reached an internal temperature of ~150-155 degrees.
Once the meatballs have reached the appropriate internal temperature remove them from the cooking grid and add them to the sauce in the dutch oven.
With a wooden spoon mix the sauce and meatballs until thoroughly incorporated.
Close the lid and allow the meatballs to continue to simmer for an additional hour. This is when the sauce really takes on a delicious flavor from the now smoke infused meatballs.
Remove meatballs and sauce from dutch oven and serve hot.