A little prepared horseradish lends a bit of a pungent kick to this easy-to-make salmon dish. Served with a simple cucumber salad, it's a healthy, delicious, light meal that you'll come back to again and again.
Preheat the oven to 475 degrees. Line a large cookie sheet with foil.
In a bowl, toss the cucumber with the vinegar, 1 tablespoon of the dill, 1 tablespoon of the oil, 1/8 teaspoon of the salt, and 1/8 teaspoon of the pepper.
In a small bowl, combine the panko, horseradish, and the remaining dill and oil. Season the salmon with remaining salt and pepper, and place on a cookie sheet, smooth side up. Press the panko mixture evenly on top of the fillets. Bake until golden brown on top and opaque throughout, about 8 minutes.
Toss the spinach with the cucumber mixture in a bowl and serve with the salmon.