Trim the tough ends off the asparagus and toss with a light drizzle of olive oil, sprinkle with salt and pepper to taste. Place on a parchment-lined sheet pan.
Nestle the salmon in the middle of the asparagus and drizzle with olive oil, sprinkle with salt and pepper and sprinkle the salmon and asparagus with lemon zest from ½ a lemon ( saving the remaining zest for the sauce).
Place in the preheated 375F oven for 16-20 minutes, adjusting time, depending on thickness of the salmon, and broiling for the last couple minutes if you like. (This piece was 1 ½ inches thick and took 16 minutes, plus 2 minute broil) for salmon cooked to medium. If cooking smaller salmon pieces, they may take less time, so check earlier and remove if needed, allowing asparagus to cook longer if necessary.