1) Heat the oil in a medium saucepan over medium-high heat. Add the onion and cook, stirring, until tender, about 8 minutes. Stir in the garlic, tomato puree, and crushed pepper and cook until fragrant, about 2 minutes.
2) Add the ham hocks, tomatoes, vinegar, sugar, salt, and pepper. Bring to a boil. Lower the heat, and simmer, uncovered, stirring occasionally, until deep red in color and has thickened, about 20 to 25 minutes. Adjust seasoning salt with pepper. Sauce will keep covered in the refrigerator for up to 3 days or freeze for up to 1 month.