Heat 1 tablespoon olive oil in a large skillet over medium heat. Add leeks and cook until they soften and glisten, about 10 minutes. Transfer leeks to bowl.
Pour remaining olive oil into skillet, add salmon and cook until just barely pink. Transfer to cutting board and let cool slightly. Using a fork, shred salmon into small pieces.
In a large bowl, whisk together eggs, whole milk, heavy cream, salt, and a generous amount of black pepper. Add cream cheese and use a wooden spoon to break up, noting there will still be small lumps. Set aside.
Roll out thawed pastry dough to fit a 9 inch shallow pie dish. Transfer dough to pie dish and use your fingers to press against the sides. Cut off excess dough and discard.
Spread leeks across the bottom of the dough. Top with salmon flakes, then pour custard mixture over the top. Sprinkle capers and dill on top.
Bake for 30-40 minutes, until the center is firm and the crust is golden brown. Let quiche cool for at least 10 minutes before serving.