Whisk together egg yolks and eggs. Combine with sugar and lime juice in small saucepan. Cook over medium-low heat, stirring constantly, 8 to 10 minutes, or until mixture is thick enough to coat back of spoon.
Stir to cool slightly. Strain into small bowl; add butter, a piece at a time, stirring until smooth. Stir in zest; let cool completely. Cover with plastic; refrigerate until needed.
Heat oven to 200 degrees. Trace three 6-inch circles on parchment; place, penciled side down, on 12-inch-by-18-inch baking sheet.
Fill clean pastry bag fitted with an Ateco #12 plain tip with meringue, reserving about 1 1/2 cups; pipe out meringue, starting in center of each circle, spiraling out to circle’s edge. Create 1-inch-tall wall of meringue peaks by piping along outside of circle using same tip to create smooth peaks, or change tips for a more decorative edge. If making bite-size tarts, follow above spiraling process on sixteen 2-inch circles, creating 3/4-inch wall.
Place the baking sheets in the oven, and bake about 20 minutes. Reduce the heat to 175 degrees, and bake 40 to 60 minutes more until meringue is dry and crisp but still white. Let stand to cool completely on baking sheets. The shells can be packed in airtight containers and stored for several weeks in dry weather.
Heat oven to 475 degrees. Fill cool meringue tarts with chilled lime curd. Rewhip remaining meringue on high speed until stiff, about 5 minutes. Fill pastry bag fitted with an Ateco #5 star tip; pipe a ring of decorative peaks on top of lime curd. Bake until lightly browned, about 2 minutes. Serve immediately.