Heat oven to 400º F. Season the salmon with ½ teaspoon salt and ¼ teaspoon pepper and place on a rimmed baking sheet.
In a small bowl, combine the bread crumbs, horseradish, parsley, and 1 tablespoon of the oil. Top the salmon with the mixture, pressing gently to help it adhere.
Roast until opaque throughout, 12 to 15 minutes.
In a medium bowl, toss the greens, vinegar, the remaining tablespoon of oil, and ¼ teaspoon each salt and pepper. Serve with the salmon.