How to Make It
Using a sharp knife, peel the oranges, taking care to remove all of the bitter white pith; working over a bowl, cut in between the membranes to release the sections. Squeeze the membranes to get 1/4 cup of the orange juice. Save the remaining orange juice for another use.
In a large bowl, whisk the orange juice and lemon juice with the olive oil; season with salt and pepper. Add the orange sections, watercress, tomatoes, hearts of palm and olives and toss well. Serve immediately.