Shaving chocolate with a vegetable peeler or a knife is one way of creating chocolate curls.
To create the smallest chocolate curls: Chill a bar or block of couverture. Line a jellyroll pan with waxed paper.
Prop the chocolate on the edge of the jellyroll pan so that the curls will fall onto the waxed paper. Draw a vegetable peeler over the chocolate lightly and quickly.
For slightly larger curls: Allow the chocolate to warm slightly at room temperature. Draw the vegetable peeler over the chocolate a little more slowly, applying a little more pressure.
For wider chocolate curls: Prop a block of chocolate on the edge of a jellyroll pan lined with waxed paper.
Place a large chef's knife at the base of the chocolate block. Hold the handle of the knife with one hand and the tip of the blade with the other, so the blade of the knife is parallel to the surface of the chocolate. (If you've never used this technique, place a cardboard sleeve over the tip of the knife so you don't cut yourself.)
Draw the knife up from the base of the chocolate block. Once again, the temperature of the chocolate and the amount of pressure you apply will determine the size and weight of the shaved curls.
Store shaved chocolate in an airtight container, in a cool place.