Preheat your oven to 400°F (200°C).
Peel and slice the carrots into rounds and cube the daikon radish into bite-sized pieces.
Toss the carrots and radish with olive oil, half of the sea salt, and half of the black pepper on a baking sheet.
Roast the vegetables for 15-20 minutes until tender and slightly caramelized around the edges.
While vegetables roast, finely chop the parsley and thyme, then mix them in a small bowl with the lemon zest.
Season the salmon fillet with the remaining salt and pepper, then brush the top with Dijon mustard.
Press the herb and zest mixture firmly onto the mustard-coated side of the salmon.
In the final 10 minutes of vegetable roasting, place the salmon on the baking sheet (or in a separate pan) and bake until the fish is opaque and flakes easily with a fork.
Transfer the roasted root vegetables to a bowl, top with the herb-crusted salmon, and drizzle with fresh lemon juice before serving.