Cut the salmon fillet into cubes and place in a shallow dish with the shiitake.
Combine the lime rind, lime juice, kaffir lime and oil and pour over the salmon and shitake. Set aside to marinate for approx 45 minutes or longer if you have time.
Thread the salmon and shitake through small bamboo kebab sticks.
Mix the yoghurt, horseradish, lime juice, kaffir lime together. Stir through the capers and cucumber and set aside.
Grill the kebabs for approx 8 minutes turning regularly to cook through evenly. Serve the kebabs with the yoghurt salsa.
Note: bamboo sticks should always be soaked in water for around 10 minutes before threading and cooking otherwise they will burn.