1. Bring broth to a boil in a large saucepan.
2. Cut cucumbers in half lengthwise.
3. Peel and seed cucumbers and then cut into 1/2-inch strips.
4. Cook cucumbers and mushrooms in broth for about 10 minutes, or just until cucumbers are crisp-tender.
5. Add green onions, salt, and pepper, cook for another minute or so and then pour soup into bowls.

Garnish with a little fresh parsley.