Step 1In a blender, combine the bell peppers, hazelnuts, garlic, lemon zest and juice, cider vinegar, one-fourth teaspoon salt and several grinds of black pepper. Pulse to combine. With the blender running, drizzle in the olive oil to emulsify and form the pesto. Taste, adjusting seasoning and flavoring as desired, and adjusting the thickness of the pesto with additional olive oil. This makes a generous 2 cups pesto, more than is needed for the remainder of the recipe; any leftover pesto can be covered and refrigerated for up to 3 days.
Step 2Remove the pesto to a bowl and stir in the chopped chives.
Step 3Heat the oven to 425 degrees.
Step 4Place the salmon fillets on a parchment-paper-lined baking sheet and drizzle the top of each fillet with a little oil. Sprinkle a pinch of salt and a few grinds of pepper over each fillet.
Step 5Place the fillets in the oven and roast until the salmon is cooked through, 15 to 20 minutes.
Step 6Plate the salmon and drizzle a little pesto over each fillet. Serve immediately.