Using an electric mixer with whisk attachment, beat egg whites, cream of tartar, salt until peaks begin to form. Add remaining granulated sugar 2 tablespoons at a time, beating well between additions. Beat in the cornstarch mixture. Add vinegar and vanilla extract; beat 1 minute, or until meringue is glossy and stands in peaks.
Form 12 meringue shells by spooning six 3" mounds onto each baking sheet. Using the back of a spoon, make a well in the center of each mound.
Place in oven and reduce temperature to 200°. Bake until meringues are firm and begin to color, about 2 hours. (They will be dry on the outside and chewy in the center.) Cool on baking sheets set on wire racks.
Meanwhile, combine strawberries, 6 tablespoons of the confectioners' sugar and lime zest and juice in a bowl. Set aside to macerate 2 hours, stirring occasionally.
In a large bowl, beat heavy cream, 3 tablespoons of the confectioners' sugar and vanilla seeds until stiff.
To assemble, spoon whipped cream into meringues. Spoon strawberries over the cream. Dust with remaining confectioners' sugar and serve.