Use a sharp knife to carefully peel the oranges. Slice the top and bottom off first so you have a solid base for holding the orange. Run the knife down the outside edge and remove the entire white pith layer. Turn the orange on it's side and slice thin circles and set them aside.
Layer the baby spinach on a platter. Sprinkle the orange slices all over the top. Pinch 2-3 oz of goat cheese into crumbles over the top. Sprinkle 1/4 cup salted pistachios over the top.
Serve with vinaigrette on the side or drizzled over the top. Everything tastes best at room temperature.