Preheat the oven to 180°C.
Cut the lemon into thin rings and put each salmon steak on top of one of them in a baking dish.
Season with salt and pepper, scatter some chilli flakes and the lemon zest on top, the pour over the wine.
Put the remaining lemon rings on top the fish, then drizzle with olive oil.
Cover the dish with foil, then bake in the oven for 10 minutes.
Meanwhile, cut off and discard the woody ends of the asparagus.
Remove the foil and arrange the asparagus around the fish.
Cover again, then steam for 5-8 minutes, depending on the thickness of the asparagus and the fish steaks.
Remove the dish from the oven and rest for 5 minutes (still covered) then serve.
You can add some dill or chives, just before serving.