To make the dressing:
Pour the olive oil and the champagne vinegar into a blender.
Add the mayonnaise and the Dijon mustard along with ¾ teaspoon of the kosher salt and the black pepper.
Process until well blended and smooth, about 1 to 2 minutes. Check for seasoning and add the additional ¼ teaspoon salt if needed.
Makes about 1-½ cups dressing.
For the salmon:
About 30 minutes before cooking, pull the salmon from the fridge, brush it with olive oil and season the flesh side with kosher salt and freshly cracked black pepper. Preheat the oven to 400-degrees.
In a large ovenproof skillet, warm the olive oil over medium heat. Add the sliced fennel and onions, sautéing for about 10 minutes or until the vegetables are tender.
Remove from the heat and place the salmon on top of the fennel and onions.
Place the orange and lemon slices over the salmon and toss the fennel fronds into the pan. Roast the salmon in a 400-degree oven for 40 minutes, or until the salmon is just cooked through.
When the salmon is cool enough to handle, break into large chunks.
For the pasta salad:
Bring a large pot of heavily salted water to a boil. Add the pasta and cook for about 11 to 13 minutes or until just tender.
Drain the pasta then pour it into a large bowl – don’t rinse the pasta. While the pasta is still hot toss it with ½ cup of the vinaigrette.
Add the chopped fennel, the red onion, dill, capers, and the roasted salmon. Pour in an additional ½ cup vinaigrette and gently stir to combine.
Serve at room temperature or chilled.