To make the marinade for the salmon, combine 3 tbsp olive oil with 2 tablespoons of Chimichurri spice, the smoked paprika, allspice, and dark muscovado sugar, then leave for 10 minutes for the flavours to develop.
In another bowl, mix together the remaining tablespoon of Chimichurri spice with the yoghurt, mayonnaise and salt; set aside.
In the mean time, coat the salmon with the marinade and let sit for another 10 minutes.
Shred the red cabbage, cut the mint into thin ribbons and combine the two in a bowl.
In a hot pan, sear the salmon on each side for about 2 minutes, then transfer it to the oven and cook for a further 5 minutes (depending on its thickness). The salmon is done when it flakes easily.
Dress the cabbage with the juice of 1 lime or lemon, vinegar, olive oil and a pinch of salt.
Arrange half of the cabbage on a plate, top with the salmon and serve with the Chimichurri yoghurt on the side or drizzled over the top, accompanied by a few lime or lemon wedges.