You can obviously use different oranges. When blood oranges are in season though, you don't want to pass them by.
To supreme an orange: Trim the top and bottom of the orange. Trim off the skin with a sharp knife, trying to remove the pith without taking off too much flesh. Taking a sharp knife, slide it along one side of the membrane of one orange 'slice' Then slice the other side, so that the orange piece is no longer attached to the membranes. Remove. Keep going along the entire orange, until each section has been removed from the membranes. Set aside.
This makes a lovely side salad with a dinner. With the addition of more nuts and cheese this can totally be a filling meal by just including a crusty baguette and some lovely olive oil.