Preheat oven to 325 degrees F. Combine the melted butter, bread crumbs, 1/4 cup of the Gouda cheese, and dill in a bowl. Spoon into a 9-inch spring-form cake pan, packing the mixture in and a little bit up the sides. Refrigerate.
Beat the cream cheese until smooth. Beat in the eggs one at a time. Finely chop half the smoked salmon slices, reserve the rest for the top. Add the chopped smoked salmon, remaining Gouda, cream, lemon zest, salt and white pepper to the cream cheese mixture and mix until well combined. Pour into prepared pan. Set pan in a larger roasting pan. Add enough hot water to come halfway up the sides of the cake pan. Bake for 1 hour and 20 minutes. Turn oven off and cool cake 1 hour with door ajar. Transfer to rack and cool to room temperature. Refrigerate until well-chilled. Run a hot paring knife around the sides of the cake, then unmould. Decorate top with smoked salmon slices, cucumber, red onion and dill. Serve with sliced bread and crackers.