Saute leeks and carrots in 2 tablespoons of the butter in kettle 4 to 5 minutes, or until tender but not browned. Cut fish into serving-size pieces; place in kettle. Add water and salt. Bring to boiling. Lower heat; cover and simmer 15 minutes or until fish flakes easily. Remove fish from kettle with slotted spoon; set aside. Add celery soup and potatoes to kettle. Bring to boiling. Cover; lower heat; simmer 5 minutes. Remove seeds from cucumber halves. Slice crosswise into 1/8-inch thick slices. Saute in a small skillet in remaining tablespoon butter 3 to 4 minutes. Add to kettle with milk, fish and dill. Bring just to boiling. Remove from heat. Serve hot. soup 34