Bring some water to a boil and blanch the ginger until tender; drain and dry; set aside.
In a mixing bowl combine oil, lemon juice, capers, salt and pepper. Just before serving, toss the spinach with most of the vinaigrette, reserving some for avocadoes. Peel avocado and slice into 3 by 1 inch pieces. Toss avocado with remaining dressing.
Set dressed spinach in the middle of each dinner plate. Place avocado slices in a crown around spinach. Place the pieces of smoked fish, alternating the sable with the salmon, around avocado. Garnish spinach with julienned ginger.