In the hot oil, saute the onion. Sprinkle with flour and mix in the paradeis pulp dissolved with warm water. Crumble the tuna and add to the sauce form. Season to taste with wine, salt and freshly ground pepper.
Sprinkle breadcrumbs over a greased gratin dish. Pour in pasta cooked al dente, press a well in the center and pour in tuna mixture. Sprinkle with parmesan cheese. Bake in the oven heated to 180 degrees for 25 minutes.