Preheat oven to 400°F/205oC Spray 2 large baking sheets with nonstick spray (or silicon baking mat).
Melt 1 cup chocolate chips in glass bowl in microwave, stirring twice, about 2 minutes. Cool slightly.
Using electric mixer, beat whites in large bowl to soft peaks. Gradually beat in 1 cup sugar. Continue beating until mixture resembles soft marshmallow creme.
Whisk in your second cup of sugar, cocoa, cornstarch, and salt in medium bowl to blend. On low speed, beat dry ingredients into meringue. Stir in peppermint extract, lukewarm chocolate and 1/2 cup chocolate chips (dough will become very stiff).
Roll 1 rounded tablespoon dough into ball (can coat in additional sugar if you want).
Place on prepared sheet. Repeat with remaining dough, spacing 2 inches apart. Bake until puffed and tops crack, about 8-10 minutes (don't overbake!). Immediately upon removing from the oven, press 1 Hershey kiss in the middle fo the cookie. Cool on sheets on rack 10 minutes. Transfer to rack; cool.