Preheat oven to 425°F. Line a baking sheet with parchment paper or foil for easy cleanup and lightly oil the surface with 1 tsp olive oil to prevent sticking.

In a small bowl whisk together 2 tbsp olive oil, lemon juice, lemon zest, minced garlic, Dijon, honey, 1/2 tsp kosher salt, 1/2 tsp black pepper, and red pepper flakes (if using) until combined and slightly emulsified.

Place trimmed asparagus on one side of the prepared sheet. Drizzle with 1 tbsp olive oil and sprinkle with 1/4 tsp kosher salt and 1/4 tsp black pepper; toss with your hands to coat and spread in a single layer so stalks are not overlapping.

Pat salmon fillets dry with paper towels, place skin-side down on the empty side of the baking sheet (space them apart). Spoon or brush about three-quarters of the lemon-garlic dressing evenly over the tops of the fillets, reserving the rest for finishing.

Roast in the preheated oven for 10–12 minutes, depending on fillet thickness, until the asparagus is tender-crisp and the salmon is opaque in the center and flakes easily with a fork. Salmon should register about 125–130°F for medium (it will continue to rise while resting).

Remove the sheet from the oven and let the salmon rest 2 minutes. Drizzle the reserved dressing over the salmon and asparagus, sprinkle with chopped parsley, and serve immediately with lemon wedges if desired.