In a small bowl, combine the dill, panko, horseradish and oil. Mix with a fork or your fingers until the oil is absorbed. Set aside.
Wash the asparagus and remove tough stem ends. Set aside
Place the salmon fillets in a baking dish, skin side down, and season with salt and pepper.
Place ¼ of the topping mixture on each fillet. Press down to secure. Add the asparagus spears to the pan and sprinkle with salt and pepper.
Bake until the topping is golden brown, and the fish is cooked to your liking, about for 4 to 6 minutes per half-inch thickness. (The FDA suggests a final temperature of 145F, I usually go less.)
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.