Photo: Kate Whitaker
Defrost the crab claws overnight in the fridge. Crack open each claw at the score marks with your hands. Alternatively, place in-between layers of kitchen paper and, using a rolling pin, strike each section to break open. Pull out the flesh and put in a bowl, discarding the cartilage from inside the pincers. Squeeze the excess liquid out of the claw meat (or from the ready prepared crab meat, if using the pots).
Place the crab meat in a small bowl with the lime zest, 2 tbsp lime juice, the chilli and 2 tbsp olive oil. Mix and season to taste. Cover and chill until needed.
Using a sharp knife, slice the top and bottom off each grapefruit, then cut away the peel and pith. Holding one grapefruit over a bowl, cut away each segment by running a serrated knife just inside the segment partitions. Once all the segments are in the bowl, repeat with the other grapefruit. Discard (or drink) any juice.
Finely slice the fennel and add to the grapefruit, then add the chicory leaves and onion. Cover and chill.
When you are ready to serve, add 2 tbsp olive oil and 2 tbsp lime juice to the grapefruit and leaf mixture as a dressing, then season. Mix and arrange on 4 plates. Spoon the crab around each salad. Serve immediately.