Heat the oil in a heavy-based non-stick frying pan and fry the salmon skin side up for 3 minutes. Turn over and cook for another 3-4 minutes. Turn the salmon fillets on the side, turning once and cook for 1 minute each side. Remove from the pan and keep warm.
Add the onion to the pan cook over a medium heat for a few minutes until softened and beginning to colour.
Add the beans and toss over the heat for a minute or two.
Add the garlic and cook for a few seconds before adding the spinach. Stir-fry the spinach until beginning to wilt then add the crème fraîche and season well. Spoon onto serving plates and sprinkle with a little more za'atar spice . Place the salmon on top and serve.