Spray a rimmed baking sheet with nonstick spray or lightly brush with any kind of oil. Place the salmon fillets on the sheet, about 1 inch apart.
In a small container or bowl, combine the olive oil, horseradish, ginger, soy sauce, and garlic. Coat the salmon with the mixture, pouring it over each piece and using your fingers so it evenly coats the sides of the pieces as well. Let sit for 10 minutes.
Roast for 12 minutes, or until it is cooked to your liking. Serve hot, with Tomato Scallion Rice, or the rice of your choice.
Notes
I think this is the perfect level of spicy without being TOO spicy, so you can still taste and enjoy the salmon. But feel free to bump it up!