Preheat the oven to 450. On a rimmed baking sheet, toss the cabbage and kale with 2 tablespoons of the olive oil and season with salt and pepper. Spread out (don't worry if it looks like a lot - it will shrink as it bakes). Roast for about 6 minutes.
Stir the cabbage and kale, season the salmon with salt and pepper and nestle it among the greens. Roast for an additional 10 minutes.
While the salmon is roasting, whisk together the rest of the olive oil, the lemon zest and juice, the dill and dijon mustard. Season with salt and pepper.
To serve place the greens and salmon on a plate and drizzle with the dill dressing.
Since you are using the zest and the juice from the lemon - organic is recommended.