Around here, we're all about efficiency and good tools. Just ask David about zesting citrus... Now if you want to make some perfect-looking strips of zest to decorate this lovely cake, you're going to need either a paring knife or a vegetable peeler. Hold the knife/peeler in one hand and lime in the other. Pull the blade across the lime skin until the top part of the peel comes off in a slice. For the best zest, use a fresh lime with unblemished peel. Use only the outside colored peel, avoiding the bitter white pith.