Finely zest the lemon and limes, peel and finely grate the ginger.
In a deep baking tray large enough to fit the salmon, combine the zest, ginger, soy sauce and mirin. Gently place the salmon fillet in the tray and spoon over the marinade, then pop it in the fridge for at least 90 minutes.
To make the salsa, squeeze the juice from half the lemon and one of the limes into a high-sided jug, and add twice as much oil. Deseed and roughly tear in the pepper and chillies, pick in the mint leaves and season well with sea salt and black pepper. Using speed one, gently mince the veg until finely chopped.
When you’re ready to cook the salmon, preheat your oven to 200 ° C / 400 ° F / gas 6.
Remove the salmon from the tray and discard the marinade. Drizzle with oil, then place it skin-side down on a large roasting tray.
Bake for 12 to 15 minutes or until cooked to your liking. Flake the salmon and dollop over the red pepper salsa. Delicious served with some steamed rice and a leafy salad.