1. Preheat the oven to 375F/190C. Place the fillets on a cutting board and drizzle with a little oil. Season to taste with pepper. Heat a skillet and cook the fish, nonskin-side down first, until browned. Turn over to brown the other side. Transfer the fish to a roasting pan and cook in the oven for 10-12 minutes, until the fish flakes easily. Melt the butter in a small pan, then let stand until separated. Pour off the clear, clarified butter into a separate pan, and discard the white salty residue.
2. Cook the asparagus for 2-3 minutes in boiling water. Drain, rinse under cold running water, drain again, and set aside.
3. Add the tomatoes, dill and lemon rind to a bowl and mix. Divide the asparagus and salmon between 4 plates, spoon some of the tomato dressing over each one, and serve.
30 mins to prepare, 30 mins to cook