Preheat the oven to 400°F (200°C). Lightly oil or spray a large baking sheet.
Arrange the salmon fillets and whole carrots (with greens on) on the prepared baking sheet in a single layer.
Season the salmon fillets with 1/2 teaspoon sea salt and 2 teaspoons ground paprika.
Drizzle the carrots liberally with avocado oil and rub or toss with your hands so they are evenly coated, then sprinkle with a little sea salt.
Bake in the preheated oven for about 25 minutes, or until the salmon is cooked through and the carrots are tender.
While the salmon and carrots bake, toast the walnuts: spread them on a baking sheet and toast in the oven for 3 to 4 minutes until fragrant and lightly golden, then let cool.
Make the carrot-top pesto: add the cooled walnuts, carrot tops (discard stems), 2 cups loosely packed fresh basil, and 2 tablespoons cider vinegar to a food processor and pulse until chopped.
With the processor running, stream in 1/2 cup avocado oil through the feed hole until the pesto reaches your desired consistency; add more oil if you want a thinner sauce.
Taste the pesto and season with up to 1/2 teaspoon sea salt, adjusting to preference (optional: add garlic or Parmesan if desired).
Serve the roasted salmon and carrots with the carrot-top walnut pesto drizzled or spooned on top.
