Combine softened cream cheese, fresh dill, lemon juice, lemon zest, black pepper, and sea salt in a small bowl. Stir for 60 seconds until completely smooth and uniformly colored, then fold in horseradish and Dijon mustard carefully to preserve the airy texture.

Wash English cucumbers thoroughly under cold running water and pat completely dry. Slice cucumbers on a slight angle into 1/4-inch thick rounds, creating 24 elegant ovals that showcase the vegetable's natural beauty and provide ample surface area for topping.

Arrange cucumber slices on a paper towel-lined baking sheet and lightly season each with sea salt. Let sit for 5 minutes while you prepare the salmon, allowing salt to draw out excess moisture that would otherwise prevent the fresh zesty smoked salmon cucumber appetizers from holding their toppings securely.

Cut smoked salmon into thin strips, then fold each strip into a small roll or accordion shape that sits attractively atop the cream cheese base. Prepare capers and red onion in small separate bowls for easy access during assembly.

Transfer the cream cheese mixture into a small piping bag or disposable pastry bag fitted with a small round tip. Pipe approximately one teaspoon of filling onto each cucumber slice, creating a slight dome that anchors the salmon and toppings while looking impressive.

Top each piped round with one folded smoked salmon piece, pressing gently to secure it in the filling. Sprinkle fresh parsley and a few capers over each bite, then add a tiny pinch of red onion for a final pop of color and sharp flavor.

Drizzle the entire platter with olive oil using a small spoon or oil mister, creating glistening appetizers that look restaurant-quality. Serve immediately or cover loosely with plastic wrap and refrigerate for up to 2 hours before your guests arrive.