Place chopped leeks, ginger, and garlic in large stockpot with splash of chicken broth. Saute for about 6 minutes, allowing veggies to brown after stock has dissolved.
Add remaining stock to pot with clementine slices, zest, bay leaf, salt, pepper and tarragon. Simmer over medium low for 20 minutes.
Remove bay leaf and puree soup in food processor or blender.