Preheat oven to 350 degrees F (175 degrees C). Line two baking sheets with parchment paper.
Combine smoked salmon, feta cheese, black pepper and garlic.
Roll out puff pastry on lightly floured surface to form a 12x12 inch sheet. Cut sheet into 16 3x3-inch squares. Place a spoonful of salmon filling in the center of each square. Pull together corners of each square to form 16 small packets. Brush packets with egg whites and place on prepared baking sheets. (The puffs can be frozen at this point. See Editor's Note.)
Bake in preheated oven until pastry is golden brown, about 20 minutes. Serve warm.
