Heat oil in soup pot over med-low heat. Add onion and sauteĢ, stirring occasionally until coated with oil.
Add water, soup mix, carrots and daikon. Bring to a boil. Reduce heat, cover and simmer 20 minutes. Season very lightly with tamari and a few drops sesame oil. Simmer 10 minutes more. Serve garnished with scallion slices.