Housed in a beautifully restored old windmill opposite the Mozia boat dock (on the 'mainland' side of the channel), this small salt museum has displays about the history of salt production in the area, including a film in multiple languages. From 4pm to 6pm on Wednesday and Saturday afternoons in summer, you can see the windmill in action.
Ask at the reception about renting bikes (€10 per half-day) and canoes (€6 per hour, summer only).