Mix non-fat sour cream, green tea poowder and tarragon in large bowl. Add grapes; mix lightly.
Meanwhile, add the gnocchi to the boiling water all at once and stir gently. Let cook until the gnocchi float to the top, then lift them out of the water with a skimmer (do not use a colander).
Add gnocchi and black pepper to sour cream mixture and mix well.
Refrigerate 3-4 hours or until chilled. Serves 4