01 - Set oven to 200°F. Line two baking sheets with parchment paper.
02 - In a clean, grease-free mixing bowl, combine egg whites and cream of tartar. Beat on medium speed with an electric mixer until soft peaks form.
03 - Gradually add granulated sugar, one tablespoon at a time, beating on high speed. Continue until stiff, glossy peaks form, about 5 to 7 minutes.
04 - Beat in salt and vanilla extract until just combined.
05 - Fit a piping bag with a large star or round tip. Use a food-safe brush to paint one red stripe, one blue stripe, and one plain section for white inside the piping bag.
06 - Carefully spoon the meringue mixture into the prepared bag without disturbing the color stripes.
07 - Pipe small mound shapes, about 1 to 1.5 inches wide, onto parchment-lined sheets, spacing the kisses 1 inch apart.
08 - Bake for 1 hour and 15 minutes until dry and crisp. Turn off oven and let meringues cool inside with the door closed for 1 hour.
09 - Gently remove meringues and store in an airtight container at room temperature for up to 5 days.