1. Preheat oven to 175 degrees. Line a rimmed baking sheet with parchment.

2. Place egg whites, granulated sugar, and salt in a heatproof bowl. Set bowl over a pot with a few inches of barely simmering water; cook, whisking constantly, until mixture is warm, frothy and sugar is dissolved, 1 to 2 minutes. Remove bowl from heat and, using an electric mixer, beat on high until stiff, glossy peaks form, about 3 minutes. Place confectioners' sugar and matcha in a small sieve; sift over egg white mixture and gently fold in with a rubber spatula.

3. Fit a large pastry bag with a 1/2-inch round tip and fill with meringue. Pipe 1 1/2-inch kisses onto prepared baking sheet. Bake until dry, rotating pan halfway through, about 2 hours. Let cool completely on sheet on a wire rack before peeling off parchment. Store in an airtight container for up to 1 week.