Zest is the yellow, perfumey, outermost layer of skin on citrus fruit. The aromatic oils found in zest are what give so much flavor to foods. The average lemon yields 1 tablespoon grated zest. A potato peeler is the easiest and quickest way of removing the entire zest from a lemon. Be sure to avoid zesting the pale pith found underneath the skin, which is bitter. For best results, peel the lemon from stem end to navel end when needing strips. Each strip can then be sliced lengthwise into needle-thin julienne. When you need the zest diced, take these julienne strips and dice them into fine tiny squares. A zester is a little apparatus that will remove the zest in tiny long shreds. This is best when you want to be decorative. A sharp paring knife works as well, but tends to leave more of the pith on the peel.