* Remove backbone but leave head and tail on fish. May substitute mackerel or sea bass. Cook the rice uncovered in 3 quarts boiling, salted water for about 12 minutes or until it is still slightly firm. Drain in a large colander and set aside to cool. In a small bowl, toss the chopped cucumber with 1/4 teaspoon of salt. Let it sit for at least 15 minutes, then drain and pat dry with paper towels. In a small saucepan, melt 2 tablespoons of butter and cook onions and cucumbers 6 to 8 minutes until soft and transparent but not brown. Transfer to a large mixing bowl and add chopped eggs, cooked rice, parsley and chives. Season with salt and pepper and moisten with a tablespoon of heavy cream, adding more if the stuffing seems too dry. Mix together lightly but thoroughly. Wash the fish inside and out under cold running water and dry thoroughly. Fill the fish with the cucumber-rice stuffing, close the opening with small skewers and crisscross kitchen string around the skewers as you would lace a turkey. Preheat oven to 350°F. In a baking dish or roasting pan attractive enough to bring to the table and large enough to hold the fish, melt 1/4 lb butter over moderate heat. When the foam subsides, place the fish in the baking dish, raise the heat and cook for about 5 minutes until it is golden brown. Carefully turn over the fish and brown the other side. Sprinkle top with half of the bread crumbs and then turn the fish over again and sprinkle the other side with the remaining bread crumbs. Pour 1/2 cup boiling water around the fish and bring it to a simmer on top of the stove. Bake uncovered in the middle of the oven for 30 to 35 minutes or until fish feels firm when pressed lightly with a finger. Serve directly from baking dish. Note: In Finland, 1 cup of finely chopped spinach, squeezed dry, is often substituted for the cucumber in the stuffing.