Preheat oven to 350 degrees. Sift together the flour, baking powder, and salt in a medium bowl.
Combine butter with confectioners' sugar in a mixer bowl, and beat on medium-high speed until pale and fluffy, about 4 minutes. Mix in the vanilla. Add the flour mixture, and continue to mix until everything comes together and forms a dough. Shape dough into a flat disc, wrap in plastic wrap, and let set in the refrigerator for an hour, or up to overnight.
Roll out dough to a little less than 1/4 inch thick (don't roll it too thin). Using cookie cutters about 1 1/4 inches across, cut out shapes. Insert the sharp end of a skewer into the cookie (you should not be able to see the skewer through the dough), pushing it about halfway into the cookie. Work slowly, and twist the skewer a bit as you go, but carefully, so that you do not break the cookie or mar the shape. Place on a parchment-lined baking sheet, and refrigerate until set, about 30 minutes. Reroll scraps and repeat.
Bake until the edges of the cookies just begin to turn golden brown, 12 to 13 minutes. Remove from the oven, and let cool completely.
To assemble each kebab, thread a kiss up onto a cookie skewer, and then add a marshmallow. Slide the treats up to fit against the cookie.