Preheat your oven to 350°F (175°C). If you prefer warm croissants, lightly toast them in the oven for about 5 minutes.
In a small bowl, mix the softened cream cheese, fresh dill, capers, and lemon juice until well combined. Season with salt and pepper to taste.
Slice each croissant in half horizontally, being careful not to cut all the way through.
Spread a generous layer of the cream cheese mixture on the bottom half of each croissant.
Layer the smoked salmon on top of the cream cheese mixture, followed by a few slices of cucumber.
Close the croissants and serve immediately, or wrap them in plastic wrap and refrigerate for up to 2 hours before serving.
Serve with lemon wedges on the side for an extra burst of flavor.