Preheat the oven to 200ºC/400ºF/ Gas Mark 6. Place the potatoes, olive oil, harissa paste and green beans on a baking tray and combine the ingredients together to coat.
Spread the ingredients out into a single layer and place in preheated oven for 30 minutes until tender.
10 minutes before the end of cooking add the salmon steaks and 5 minutes before the end of cooking add the cherry tomatoes.
Serve on a bed of wilted spinach or seasonal greens.