I've made something similar to this in the past, but somehow never posted about it. I was in Utah this weekend and needed to do something with a filet of Costco salmon. Here's my solution, which also uses fresh in-season asparagus. In late summer and fall, when asparagus isn't so plentiful, it tastes great with green beans.
loosely inspired by The Barefoot Contessa Cookbook
1 filet (approx 2.5 lb) salmon
1 large bunch (2 lb? How big are the packages at Costco?) asparagus, ends snapped off and snapped into two-inch pieces
Spray salmon with olive oil and sprinkle with salt and pepper and bake at 400 degrees until just firm and opaque throughout. Let cool to room temperature and then refrigerate. Blanch asparagus pieces in boiling water for 30-90 seconds, depending on thickness of spears. Let cool and refrigerate also.
juice of one lemon
twice as much olive oil as lemon juice
1 pkg fresh dill, leaves stripped and minced (about 3-4 T)
3 T capers, minced
2 ribs celery, diced fine
1/2 red onion, chopped fine
1/2 or more English cucumber, cut into quarter-rounds
salt and freshly ground black pepper to taste
Mix lemon juice, olive oil, dill and capers with some salt and pepper, then stir in remaining ingredients and reserved salmon and asparagus. Adjust seasonings and serve.