Make crust: Blend all ingredients in processor until small clumps form. Press mixture onto bottom and up sides of 9-inch-diameter tart pan with removable bottom. (Can be made 1 day ahead; chill.)
Make filling: Preheat oven to 325°F. Stir condensed milk and next 3 ingredients in medium bowl to blend. Set condensed milk mixture aside.
Using electric mixer, beat egg whites with sugar in large bowl until soft peaks form. Using rubber spatula, gently fold 1 1/2 cups condensed milk mixture into whites. Fold remaining milk mixture into whites until just incorporated.
Pour mixture into prepared crust. Bake until filling puffs up slightly and tester inserted into center comes out with some moist filling attached, about 40 minutes. Cool tart completely on rack. Chill until cold, at least 2 hours and up to 8 hours. Garnish tart with whipped cream and lime slices.