Position the rack in the centre of the oven and heat the oven to 400°F.
Heat a saucepan over a medium heat.
Add the coriander seeds and stir until fragrant, about 30 seconds. Add 3 cups of water, the lemon zest, and 1 tsp. of salt; turn the heat up to medium high.
Whisk in the polenta and cook, stirring often, until thick and creamy, about 20 minutes. (If the polenta gets too thick, loosen with a little hot water.)
Meanwhile, melt the butter in a small saucepan. Season the Norwegian salmon lightly with salt and pepper and arrange in a 9x13inch baking dish with space between each piece.
Remove the butter from the heat, stir in the harissa and lemon juice, and pour it over the fish.
Bake, basting every 5 minutes or so, until cooked through (the fish will flake easily), about 15 minutes.
If necessary, cover with foil to keep warm.
Divide the polenta among 4 shallow bowls or plates. Top with the Norwegian salmon and spoon the butter over the top.
Top with the parsley and serve with the lemon wedges.