Heat oven to 425°F (220°C). Toss potatoes and sprouts with 1 tbsp oil, salt, pepper, and paprika; spread on large rimmed sheet and roast 15 minutes.
Whisk maple syrup, Dijon, soy sauce, garlic, and remaining 1 tbsp oil in bowl. Pat salmon dry; lightly season with salt and pepper.
Push vegetables aside; center salmon skin-side down. Brush half the glaze over salmon and a little over vegetables.
Roast 10–12 minutes more until potatoes tender and salmon fork-flaky. Brush remaining glaze; optionally broil 1–2 minutes for color.
Squeeze lemon over; garnish with parsley and serve.