Peel tomatoes; place in a deep bowl.
In a screw-top jar combine oil, vinegar, parsley, green onion, marjoram, 1 tea spoon salt, and 1/4 teaspoon pepper.
Pour over tomatoes.
Cover and refrigerate several hours or overnight, spooning herb mixture over tomatoes occasionally.
At serving time, spoon herb mixture over tomatoes again.
If desired, serve on lettuce-lined platter