The trick protects your fingers from ever having to navigate the spice zone, even giving you a convenient handle on the stem end. It's also quite easy to do and makes your prep so much faster. And it naturally separates out the seeds, leaving them behind on the grater, which you can add back in for texture if you like. (Note that the spicy compound capsaicin is primarily held in the spongy white interior ribs, so if you've already grated those in, your mix will be spicy whether you leave all the seeds behind or not.) A Spicy Perspective's Sommer Collier calls for baking at 400° F, which works just fine, but ever since I learned about slow-roasting salmon, I've taken to the more forgiving pace and tender results, so I've dropped the temperature a tad here—it's flexible, depending on your preferred texture (the lower the temperature, the softer the salmon will be), how vigilant you are, and the temperature your oven perhaps already is. Adapted slightly from Sommer Collier of A Spicy Perspective. —Genius Recipes
Preheat the oven to 300° F. Line a large rimmed baking sheet with parchment paper and lay the salmon fillet on it. Pat dry with a paper towel.
Whisk the oil, lime zest, and garlic together. Grate the jalapeño and smell for spiciness. If it is very spicy (or you are sensitive to spice) add only half the grated pepper. Otherwise, add it all to the oil mixture. Pour or spoon the mixture over the salmon fillet and salt and pepper liberally.
Bake for 10 to 15 minutes, until just cooked through, but not dry. The fish should feel just firm in the center and should be just beginning to flake when you poke into it. An instant-read thermometer should read 120° F. Squeeze lime juice over the top and serve warm.