In a large saucepan or stockpot, cook sausage over medium-high heat, stirring frequently, until thoroughly cooked and no longer pink. Stir in tomatoes and green chiles; cover and cook 2 minutes. Stir in cheese and salsa; add green onions if desired. Reduce heat to medium and cook uncovered until melted, stirring frequently. Stir in chopped tomato if desired. Serve hot with crackers or pita crisps.