Place potatoes in a plastic bag with 1 teaspoon of olive oil, salt and pepper. Toss and shake to coat. Pour onto 1 side of a cookie sheet. Place beets in same bag, add 1 teaspoon of olive oil, salt and pepper. Toss and shake to coat. Pour onto same cookie sheet as potatoes, but keep divided. Place fennel in same bag with remaining teaspoon of olive oil, salt and pepper. Toss and shake to coat. Place in a single layer on a cookie sheet. Cook all vegetables, turning once until golden and cooked through, about 20 to 25 minutes. Set aside.
Place salmon, skin side down, in a non-stick pan with an oven-proof handle and season with salt and pepper. Place in oven and cook until fork tender and cooked through, about 15 to 17 minutes.
Distribute orange slices among serving plates. Distribute potatoes, beets and fennel. Divide salmon into four pieces. Place one piece on each plate. Drizzle one tablespoon tapenade vinaigrette per plate over salmon and veggies.
Whisk together all ingredients in a small non-reactive bowl. Taste and adjust seasonings.
Place all ingredients in a food processor and pulse until finely chopped and combined. Taste and adjust seasonings with salt and pepper.