In large bowl, mix beef, pork and flour until meats are evenly coated. In 12-inch skillet, heat oil over medium-high heat. Add meats; cook 8 to 10 minutes, stirring frequently, until browned on all sides (if necessary, cook meats in batches).
Spray 4- to 5-quart slow cooker with cooking spray. In cooker, mix browned meats and remaining ingredients except green onions.
Cover; cook on Low heat setting 7 to 9 hours. Before serving, skim off fat; sprinkle with green onions.