Prepare grill, pan, or heat oven to 350 degrees.
Season salmon filets.
Coat grill, pan or baking pan with cooking spray.
Grill, cook or bake fish until flakey when tested with a fork.
The onions can also be grilled, cooked, or baked with the salmon.
Place salad greens on 4 salad plates.
Arrange 2 ounces of salmon, the onions, grapefruit sections, and Manchego cheese evenly over the greens on each plate.
Drizzle Blood Orange Vinaigrette evenly over each salad.