For the pavlova: Preheat the oven to 350 degrees F.
In an electric mixer fitted with a whisk attachment or using a hand mixer, whip the egg whites, cream of tartar, and salt in a clean, dry bowl until foamy. Add the granulated sugar, cornstarch, vinegar, and vanilla, and continue whipping until stiff, smooth, and glossy, about 8 minutes more. Place the meringue in a pastry bag fitted with a large plain tip.
Line the sheet pan with the parchment. Pipe 2 1/2-inch wide disks of meringue onto the sheet pan in rows spaced evenly apart. Using the back of the spoon, swirl the meringue to form a few peaks on each disk.
Bake in the center of the oven for 10 minutes, then reduce the heat to 300 degrees F and bake until the meringue has puffed up and cracked on the top and the surface is lightly browned to the color of cafe au lait, about 30 minutes more.
To make the kiwi sauce: Puree the peeled cut up kiwi slightly. Pass the puree through a fine strainer. Add sugar to taste and chill.
For the whipped cream: Whip the heavy cream and brown sugar together until stiff. Spoon it in the center of the cooled pavlovas. Top with mango slices, lychee nuts, and raspberries.
To serve: Spoon some kiwi sauce on the plate and place the pavlova on top.
The meringue will expand so leave some room in between when piping onto the sheet pan. If you puree the kiwi too much it will pulverize the seeds and make the sauce look likes it's pepper-laden.