Preheat oven to 200°C. in a mortar and pestle, grind fennel seeds to a course powder, then add the rosemary and orange zest and lightly crush, season with salt and pepper.
Generously apply fennel mixture to topside of salmon fillets. Heat olive oil in a cast iron skillet over medium-high heat. Add salmon, skin side down and sear for 2 minutes then flip and sear for a further 1 minute.
Transfer pan to the oven and bake roast for 4 minutes. Remove from oven and allow to rest for 2 minutes.
While salmon is resting, arrange spinach, cucumber and radish on serving plates. Top with salmon then sprinkle over chives and macadamias. In a bowl, combine olive oil, lemon juice and dill then whisk until the mixture turns a pale yellow. Drizzle over salads and serve.