Start by segmenting the orange. A serrated knife is useful for this. First, cut off the top and bottom ends of the orange so you can set it flat on your chopping board. Working from top to bottom, slice away the peel and white pith, following the curve of the fruit. Insert the knife between one of the segments and its connective membrane and gently slice into the middle of the fruit. Then slice into the other side of the segment to release it from the membrane and lift it out. Repeat with the remaining segments.
Put the segments in a bowl with all the remaining ingredients and gently toss together. Season generously to taste. Cover and refrigerate the salad for about 30 minutes before serving.