1 Peel the onions and cut into wedges.
2 Peel 1 orange so that the shell and all the white skin is removed. Cut orange into slices and chop coarsely.
3 Rinse the remaining orange in hot water, wipe dry and grate the peel finely. Cut in half and squeeze orange.
4 Rinse basil, shake dry, pluck leaves and chop coarsely. Chop pistachios.
5 Rinse salmon slices, pat dry and coat with oil. Spread the pistachios on one side of the fish slices.
6 Heat the remaining oil in a skillet and cook the onions over medium heat for 4-5 minutes while stirring. Season with salt and pepper.
7 Add zest, orange juice and vinegar to the skillet and continue cooking, covered, for 3 minutes.
8 Add orange pieces to the onions, stir in basil. Transfer to a plate.
9 Wipe the skillet, then return to heat. Season fish slices lightly with salt.
10 Add salmon slices pistachio side down in the skillet and cook over high heat for 30 seconds. Turn over, cook another 30 seconds, arrange on plate with orange and onion pieces and serve .