Position rack in center of oven and preheat oven to 300°F. Line large baking sheet with parchment paper and draw a 15 centimeter circle on paper. Turn paper over.
In bowl of stand mixer fitted with whisk attachment, beat egg whites until foamy. Gradually add sugar, beating on medium-high speed, for ten minutes, or until firm glossy peaks form. Beat in vinegar, vanilla, and salt. Sift cornstarch over meringue and gently fold in.
Using large ice cream scoop or large spoon, dollop 12 mounds of meringue onto prepared sheet, following outside edge of circle. Using back of scoop, smooth and flatten top of meringue.
Place meringue in oven, immediately reduce temperature to 220°F and bake one hour and five minutes, or until meringue is crisp on outside but still has a marshmallow-like center and puffs ever so slightly. Turn off oven, prop oven door open with wooden spoon, and leave meringue in oven 30 minutes, then remove from oven and cool completely.
To assemble Pavlova wreath:
Scoop out firm, thick white layer of coconut cream that floats atop coconut water in can, and transfer it to large chilled bowl. Reserve coconut water for another use. Using electric handheld mixer, whip coconut cream on high speed two minutes or until soft peaks form. Gently fold in whipped heavy cream.
Gently remove Pavlova from parchment paper and place on large round platter. Spoon whipped coconut cream mixture over Pavlova. Spoon half of passion fruit pulp over cream. Decoratively arrange mango and pineapple over cream. Top with remaining passion fruit pulp and toasted coconut.
Using serrated knife, cut Pavlova into wedges and serve.