If using fresh limes, zest limes the night before and leave on a plate overnight so the zest has a chance to dry out.
Mix all ingredients together well. Pour into a small jar.
Notes
For extra lime flavour, squeeze a little lime juice over the popcorn. After zesting the limes, squeeze and collect the juice. If you don't need it right away, freeze it in ice cube trays for later use. Yield Enough to fill a 1 ounce jar.