Preheat oven to 425°F; line a large baking sheet with parchment.
Whisk mustard, honey, 1 tablespoon oil, garlic, lemon juice, paprika, pepper, and 1/4 teaspoon salt in a small bowl until combined.
Toss potatoes with remaining oil and salt; spread on one side of sheet. Roast 10 minutes.
Remove sheet; add beans and salmon skin-side down. Brush salmon generously with glaze.
Bake another 12-15 minutes until salmon is cooked through and flakes easily and vegetables are tender.
Brush salmon with remaining glaze; garnish with parsley. Serve immediately with potatoes and beans.