Place walnuts in food processor and chop coarsly. Add bread crumbs, lemon rind, olive oil and dill. Pulse until crumbly. Mixture should stick together. Season. Set aside.

 Arrange salmon fillets skin side down on parchment paper-lined baking sheets. Brush tops with mustard.

 Spoon 1/3 cup of walnut crumb mixture over each fillet. Press into mustard. Cover with plastic wrap and refrigerate for up to 2 hours.

 Bake at 350° F 15-20 minutes, or until salmon flakes with a fork. Just before serving, sprinkle each with 1 teaspoon lemon juice.

Source: California Walnut Board