Put olive oil, lemon zest, and mustard in a small bowl and stir to combine. Put salmon in an ovenproof baking pan in which it fits in a single layer without overlapping. Spread olive oil mixture evenly over both sides of fillets. Cover and refrigerate for 20 minutes.
Preheat oven to 400°.
Remove salmon from refrigerator and add water. Sprinkle salt over fillets and season with pepper. Bake just until an instant-read thermometer registers 127°, approximately 7 to 9 minutes depending on the thickness of the fillets. Salmon should be opaque and beginning to flake.
Whisk the already made Olive and Mint Vinaigrette to ensure that it’s evenly blended. Drizzle over fillets and serve immediately.