To make the marinade you need to mix together the ginger, lemon and lime zest, soy sauce, and mirin. Pour this into a large plastic sandwich bag, place the salmon fillet into the bag, scrunch it all together and then tie a knot in the top. Place in the refrigerator to chill for 1 1/2 hours
Preheat the oven to at 375 degrees F (190 degrees C /Gas 5) Place the sweet potatoes on a roasting tray and sprinkle with salt. Bake in the oven for about 1 hour.
Now make your pepper salsa by mixing your red peppers and chillies with the lemon and lime juice, olive oil, and mint.
After a couple of hours remove the salmon from the marinade. Get a griddle pan hot then place the salmon skin side down on it for a couple of minutes. Then finish off in the oven OR bake for 10 minutes in the griddle. Serve the salmon with the salsa and the baked potatoes.