Salmon cucumber sushi rolls

Name: Salmon & cucumber sushi rolls
Ingredients: 2 nori sheets; 100g skinless salmon fillet (use really fresh), thinly sliced lengthways; ¼ cucumber, deseeded, thinly sliced lengthways; squeeze wasabi, plus extra to serve; pickled sushi ginger, to serve; light soy sauce, to serve; salmon roe, to serve (optional); 100g sushi rice; 2 tsp saké or mirin (optional); 1 tbsp caster sugar (omit if using mirin); 25ml rice vinegar