Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
Pat the salmon fillets dry using paper towels to remove excess moisture.
In a shallow bowl, whisk together the ground flaxseed meal, lemon zest, salt, and black pepper until well combined.
Brush the top surface of each salmon fillet with a thin, even layer of Dijon mustard to act as a binder.
Press the mustard-coated side of each fillet firmly into the flaxseed mixture to create an even crust.
Place the fillets on the prepared baking sheet, crust-side up, and drizzle lightly with olive oil.
Bake for 12 to 15 minutes, depending on thickness, until the internal temperature reaches 145°F (63°C) and the salmon flakes easily with a fork.