Heat the oven to 425°F and line an 18-by-13-inch rimmed sheet pan with parchment rated for that temperature. Toss asparagus and beans with 1 tablespoon oil, 1/4 teaspoon salt and pepper and spread around the pan edges.
Pat salmon dry and arrange skin-side down in the center. Sprinkle with remaining salt and spread Dijon thinly over each fillet.
Mix panko, lemon zest and remaining oil in a small bowl. Press a light layer onto the mustard-coated salmon.
Roast for 12 to 16 minutes until the salmon reaches 145°F, asparagus is tender and crumbs are golden; check thinner fillets early.
Drizzle lemon juice over the beans and asparagus. Serve 1 salmon fillet with one-quarter of the vegetables and beans per portion.