Place crackers in a food processor; process until finely ground and crumbs measure about 1 1/3 cups. Add 2 tablespoons sugar and butter; pulse 6 times or just until mixture resembles coarse meal. Add egg white; pulse 10 times or just until blended (do not allow mixture to form a ball). Press into bottom and up sides of a 9-inch tart pan coated with cooking spray. Bake at 350° for 10 minutes; cool on a wire rack.
Combine cream cheeses, remaining 2 tablespoons sugar, 3 tablespoons Uniq Fruit and Lemon Marmalade, and salt in a medium bowl. Beat with a mixer at high speed until smooth. Spoon cream cheese mixture into prepared crust; cover and chill 1 hour.
Just before serving, place fruit sections onto several layers of heavy-duty paper towels; pat gently with additional paper towels to dry (do not press down). Place remaining 2 tablespoons Uniq Fruit and Lemon Marmalade in a small microwave-safe bowl. Microwave at MEDIUM-HIGH (70% power) 10 seconds or until melted. Arrange fruit sections over cream cheese filling, and brush with melted marmalade. Slice into 10 wedges.