Combine first 3 ingredients in a shallow dish, and dredge liver in flour mixture.
Cook liver in oil in a large skillet over medium-high heat until browned, turning once. Remove liver, reserving drippings in skillet.
Add onion, bell pepper, and garlic to reserved drippings, and sauté until tender. Add liver, tomato, bay leaf, and salt; cover, reduce heat, and simmer 10 minutes. Remove and discard bay leaf. Serve over grits.