Half the avocado, remove the stone, peel and cut into small chunks. Cut the cucumber into small chunks and add to the avocado along with the dill and rice vinegar. Season to taste and divide between two plates.
Preheat a ridged grill pan until very hot. Brush the oil over the salmon fillets. Season with salt and freshly ground black pepper and cook, flesh side down, for 5 minutes or until lightly charred. Turn and cook for a further two minutes until cooked through. Serve with the salad.