1. Spray large saucepan with cooking spray and saute onion over medium heat, 3-5 minutes until glassy.
2. Add cucumbers and cook for 5 minutes longer.
3. Add flour and cook 1-2 minutes.
4. Add the broth, heat to boiling, reduce to simmer, cover, and cook for 10 minutes.
5. Process soup in a food processor or blender until smooth.
6. Stir in the milk (soy to keep the soup vegan, or dairy milk for vegetarians).
7. Season to taste with salt and pepper. Refrigerate for 3-4 hours, if serving cold.
8. Pour soup into bowls and top with a cucumber slice and paprika.
