Make filling: In a bowl beat cream cheese until fluffy. Quarter eggs and with back of a spoon force through a coarse sieve into cream cheese. Add scallion and stir well. Filling may be made 1 day ahead and chilled, covered. Bring filling to room temperature before proceeding.
To make egg sheets: In a bowl dissolve cornstarch in water and whisk in eggs and salt until smooth. Brush a non-stick skillet measuring 6 inches across bottom lightly with oil and heat over moderately high heat until hot but not smoking. Half-fill a 1/4-cup measure with egg mixture. Remove skillet from heat and pour in 1/8 cup egg mixture, swirling skillet to coat evenly. Return skillet to heat and cook egg sheet until set, 10 to 15 seconds. Loosen edges of egg sheet with a heatproof rubber spatula and turn sheet over. Cook egg sheet until set, 5 to 10 seconds more, and slide onto a plate. Make more egg sheets with remaining mixture in same manner, brushing skillet lightly with oil each time. Egg sheets may be made 1 day ahead and chilled, wrapped in plastic wrap. Makes 8 or 9 egg sheets.
On a work surface arrange 2 egg sheets, side by side and overlapping by 1-inch. Put a dab of filling between sheets where they overlap (to act as glue) and press sheets together gently. Spread 1/2 cup filling on overlapping egg sheets, leaving about a 1/2-inch border on each long side. Fold in border of long side nearest you and tightly roll up sheets jelly-roll fashion into 1 (11-inch-long) roll. Wrap egg sheet roll in plastic wrap and chill 1 hour, or until firm. Make 3 more egg sheet rolls with remaining egg sheets and filling in same manner. Egg sheet rolls may be made 1 day ahead and chilled, wrapped well.
Discard plastic wrap and trim ends of egg sheet rolls. Cut rolls crosswise into 3/4-inch pieces. Arrange pieces, cut ends up, on a platter and top each with about 1/4 teaspoon caviar.
Recipe courtesy of Gourmet Magazine