Steam green beans until beans are just tender.
Cook bacon until lightly browned in large skillet. Remove bacon; reserve dripping. Crumble bacon when cool. Add onions to bacon drippings. Cook until tender but not browned, about 3 to 4 minutes.
Add corn syrup, salt, lemon juice and 1-1/2 cups water. Bring to a boil. Combine corn starch and cold water in a small bowl; whisk into sauce. Cook for 1 minute after sauce comes to a boil. Stir in bacon.
Pour sauce over green beans. Toss to mix well; serve immediately.