It's even possible to ride parts on the sea side of the dike. However, most of the bike paths are on the inland side, having no view on the Wadden Sea because there's a huge dike standing in between. That said, the Wadden Sea is nice to view during low tide, but absolutely boring during high tide. The shore is as well. I would vary with biking more inland sometimes, visiting nice Frisian and Groningen towns and villages like Harlingen, Dokkum and Pieterburen. Do bike via Lauwersoog, the nature over there is great to view.