Preheat oven to 400°F Coat a rimmed baking sheet with cooking spray.
Combine lemon zest, almonds, dill, 1 T oil, salt and pepper in a small bowl. Place fish on the prepared baking sheet and spread each portion with 1t mustard. Divide the almond mixture among the portions, pressing it onto the mustard.
Bake the fish until opaque in the center, about 7-9 minutes, depending on thickness.