Add vinegar, sugar, and soy sauce into a jar and shake until sugar is dissolved. Add oil and shake. Sometimes I cut back on the amount of oil and sugar and use 1/2 cup of each. Just a matter of taste.
Saute ramen noodles and walnuts in margarine until slightly golden. Drain and cool.
Combine lettuce, green onion, and topping in a large bowl. When ready to serve, shake dressing and pour on salad, then serve. Do not put dressing on until ready to serve. Dressing will being breaking down the lettuce.