Combine all ingredients, except clams and green onion, in a medium pot and gently simmer 5 minutes. Add the clams, cover and cook just until they open. Divide the clams and liquid among 2 bowls, sprinkle with green onion, and serve.
Note: Before cooking the clams, ensure all are closed or close when tapped. Discard any that do not close - they are dead and should not be eaten.