Preheat the oven to 400°F/200°C.
Lightly oil baking sheet or coat with nonstick spray. Whisk together lemon juice, Dijon mustard, garlic, dill, oregano, thyme, and rosemary in a small bowl. Season with salt and pepper to taste. Set aside.
Place the zucchini in a single layer on the oiled/sprayed baking sheet. Drizzle with olive oil and season with salt and pepper.
Add the salmon filet to the single layer and brush it with the lemon-mustard mixture.
Place into the oven and cook until the fish flakes easily with a fork, about 16-18 minutes.
Serve immediately. Garnish with parsley, if desired