Peel the oranges and use a knife to remove all the pith. Working on a large plate or rimmed surface to catch the juices, cut the oranges crosswise into 1/4-inch/0.5 cm slices. Separate the slices into segments, discarding any remaining white pith and connecting tissue. (This may seem finicky, but it’s quickly done.) Transfer the cleaned segments to an attractive bowl and add the olives. Set the juice aside in a small bowl.

Combine the coriander, garlic, and salt in a mortar or a bowl and use the pestle or the back of a spoon to pound or press to a paste. Add the mint, chile flakes or pimentón, and olive oil and stir to blend well. Stir in the reserved orange juice. Taste the dressing and add the sugar, if you wish.

Pour the dressing over the oranges and olives, toss lightly to coat, and serve.