In saucepan combine tomatoes, onion,sugar,3/4 tsp. salt, paprika and pepper. Bring to a boil. Reduce heat. simmer gently for 10 mins. Press mixture through a sieve. In separate saucepan melt margarine. Stir in flour, salt and pepper. Cook stirring over low heat until mixture is smooth and bubbly. Remove from heat. Slowly add milk