Toast fennel and cumin seeds in a dry pan until fragrant.

Grind the toasted seeds and lemon zest in a spice grinder until finely ground.

Season the salmon with salt and pepper.

Brush one side of the salmon fillet with Dijon mustard and coat with the ground spice mixture.

Heat olive oil in a large, nonstick skillet over moderately high heat.

Add the salmon, coated side down, to the skillet.

Cook until lightly browned, about 3 minutes.

Carefully flip the salmon and cook until the skin is crisp.

Transfer the salmon to a cutting board.

In a large bowl, whisk together lemon juice, remaining mustard, and olive oil.

Season the dressing with salt and pepper.

Add the sliced fennel and parsley leaves and toss to combine.

Cut the salmon into 4 pieces.

Serve immediately with the fennel salad.