Preheat the oven to 200°C.
Mix the spices in a small bowl and spread them onto a plate.
Press the salmon fillet into the spice mix to coat it thoroughly.
Heat 15ml of olive oil in an ovenproof frying pan and sear the salmon on both sides until golden.
Place the pan in the oven and bake for 4-5 minutes until the fish is cooked through.
Whisk the remaining olive oil, vinegar, and mustard in a bowl until thickened.
Stir the herbs, onion, and courgette into the mustard emulsion to form the salsa.
Serve the salmon on a plate with the herb salsa spooned around the edges.