Fresh Salmon Marinated in Pink Grapefruit with Avocado

• 450 g/1 lb fresh boneless salmon
• 1 large pink grapefruit

Slice the salmon as thinly as possible and remove and discard any dark meat from the slices. Remove the zest from the grapefruit and squeeze out the juice. Mix these with the cayenne pepper, then place the slices of salmon in this marinade so that they are completely covered. The salmon can be left for anything from 1 hour to 24 hours – personally, I think it is at its best aft