Remove tomatoes from the can, reserving the juice in which they are packed. Using your hands, crush the tomatoes, gently remove and discard the hard core from the stem end and any skin or tough membrane. Set aside.
Put oil in a large, nonreactive saucepan over medium-low heat. If using fatback, cut it into small pieces and add to the pan. Saute for about 5 minutes or until all fat has been rendered. Remove and discard fatback. Add onion and saute for 3 minutes or until translucent and just beginning to brown. Stir in garlic and saute for 30 seconds or until just softened. Stir in tomatoes, reserved juice, and salt. Raise heat, and bring to a boil. Immediately reduce heat to a very low simmer and cook for about 1 hour or until flavors have combined and sauce is slightly thickened. If you prefer a thicker sauce, cook for an additional 15 minutes.
Stir in basil, oregano, and pepper, and cook for an additional minute. Remove from heat and serve.