Break spaghetti in half, and cook as directed on package until al dente; drain. While spaghetti is warm, combine with eggs and parmesan cheese. Press spaghetti into bottom and up sides of a well greased, 10" pie plate with a spoon. Saute onion in margarien, mix with sour cream and spread over crust. At the same time, brown sausage in large skillet; drain fat. Stir in tomato paste and water. Bring to a boil; reduce heat. Simmer uncovered 10 minutes, stirring occasionally. Spoon over sour cream mixture. Cover dish with foil, and freeze. To prepare for serving, thaw pie and cheese. Bake pie uncovered in preheated 350 oven for 25 minutes. Arrange mozzarella slices on top. Return pie to oven until cheese melts.
