Boil the dumpling, drain, and set aside. (Note: When the dumpling floats to the surface it is ready. You can double check by cutting one with a knife or edge of a spoon.)
Boil the smoked herring, clean and break into small pieces.
In a medium sized pot, heat the oil over a medium flame and saute the onion, garlic and chadon beni. Add the tomatoes and allow to cook for about 1 1/2 minutes.
Then add the smoked herring and mix thoroughly with the rest of ingredients,and add pepper (optional). To make a little sauce you can add about 1/2 cup of water and allow to simmer for approx. 2 minutes.
Serve hot with the dumplings.