Before you start, preheat oven to 220°C (or 200°C fan bake). Bring a medium pot of salted water to the boil.
Pat salmon dry and remove any remaining bones. Place on a lined oven tray and rub with Italian spices and oil. Season with salt and top with seeds.
Cook salmon for 8-10 minutes or until cooked to your liking. Using a spoon, flake cooked salmon into large pieces.
Bring couscous to the boil in a medium pot on high heat. Once boiling, turn off heat, add couscous and salt, stir, cover and leave for 5 minutes. Fluff up grains with a fork.
Prep asparagus. Add asparagus and peas to pot of boiling water and cook for about 3 minutes, until bright green and tender. Drain and refresh under cold water. Drain well, return to pot and toss with oil and vinegar. Season with salt and pepper.
Serve couscous topped with lettuce, veggies, salmon and horseradish sour cream.