Bring lg, deep pan of boiling water to boil. Add asparagus and cook 4 mins.
Remove asparagus and set aside.
Bring water back to boil and add potato halves and cook 10-12 until tender.
Drain until needed.
Season Salmon and place 2 lemon slices on top of fillet.
Bring a wide shallow pan of water to a simmer. Carefully add salmon and lemon slices, cover and cook for 5-6mins. Or until cooked through.
Meanwhile, whisk the lemon juice, shallot, tetragonal and vinaigrette and season well. Toss the lettuce in half of the dressing, then arrange on p,ate.
Top with the asparagus and potatoes, flake over the salmon and serve with the remaining dressing drizzled over.