Preheat the oven to 400°F. Place salmon filets on a baking sheet lined with parchment paper. Drizzle with 2 tablespoons of olive oil and season with salt, pepper, and fresh herbs. Top with lemon slices.
Toss asparagus with the remaining olive oil, salt, and pepper. Arrange around the salmon on the baking sheet.
Bake for about 12-15 minutes, or until salmon is cooked through and asparagus is tender.
Meanwhile, prepare the couscous according to package instructions.
Serve the baked salmon and asparagus over a bed of fluffy couscous.