Preheat oven to 400F. Place 2 salmon burgers on a baking sheet lined with parchment paper and bake the burgers for 9-11 minutes, until the internal temperature reaches 160F.
Meanwhile, make the slaw. Place onions in a medium size bowl, sprinkle with salt and pepper. Add lettuce, lemon juice, dill, mayo and capers. Sprinkle with salt and pepper again, stir, and set aside.