Add the Ritz crackers, arugula, and olive oil (or melted butter) to a food processor and pulse until finely ground and well combined.
Press the mixture firmly into the bottom of a 6-inch springform pan or ring mold to form an even crust. Set aside.
In a mixing bowl, combine the softened cream cheese with 2 oz of finely chopped smoked salmon, chives, and lemon zest. Mix until smooth and evenly blended.
Spread the cream cheese mixture over the prepared crust and smooth the top with a spatula.
Refrigerate for at least 15 minutes, or until lightly set.
Carefully remove the mold and garnish with the remaining smoked salmon, fresh dill, pink peppercorns, and extra lemon zest before serving.