To a large skillet over medium heat, add the oil once hot add in the sausage, onion, and minced garlic break the sausage up with a spatula and cook it through.
Remove the sausage and onions to a bowl lined with paper towels.
Cook rice:
To the same pan we cooked the sausage in add the rice and water, stir everything well.
Bring this up to a simmer then turn to low and let simmer covered for 7 minutes.
Add tomatoes:
Once the rice is tender, add back in the cooked sausage and diced tomatoes.
Stir together and let simmer for 2-3 minutes.
Add in cheese:
Stir in the mozzarella and parmesan, let the cheese melt down, then serve on a dinner plate with your favorite sides!