Preheat oven to 400˚F. Line a rimmed baking sheet with parchment paper.
In the bowl of a food processor or in a blender, add avocado, cream cheese, lemon juice, garlic, and salt. Process until smooth. Cover and refrigerate until ready to use.
Gently roll out puff pastry sheet on a clean, floured surface slightly. Cut the sheet into 9 equal sized squares. Using a knife, score a thin border around the edges of each square. Use a fork to poke all over the center to the pastry.
Place squares on the lined baking sheet.
In a small bowl, whisk together egg and 1 tsp water. Brush the squares with the egg wash.
Bake for 10 to 12 minutes, until golden brown. Cool for 5 minutes.
Spread avocado cream cheese in the center of each pastry square. Top with a piece of smoked salmon. Sprinkle with chopped dill, chives, capers, and coarse salt.