Finely zest the lemon. Avoid the bitter white pith and try to just get the yellow zest on the outer edges.
Add sugar and lemon zest to a medium bowl. Use your fingers to rub the sugar granules into the lemon zest until fully combined and no clumps of lemon zest remain.
Store in an food-safe, airtight container.
To jar more for later: Preheat oven to 225ºF. Line a baking sheet with parchment paper. Spread the sugar mixture evenly over the parchment-lined baking sheet. Bake for 60 to 70 minutes, until zest has dried. Let cool. If done, the zest should crumble when you rub it between your fingers. Use within 12 months if stored in a cool, dry place.
To rim a glass: Place lemon sugar on a plate. Rub a lime wedge around the edge of the glass. Roll the rim of the glasses in the sugar to coat the rim.