Make sushi rice: Rinse and drain rice 3 times or until water runs clear. Place rice in sieve over a bowl. Set aside for 10 minutes to drain.
Place rice and 2 cups cold water in a small saucepan over medium heat. Cover. Bring to the boil. Reduce heat to low. Simmer, covered, for 12 minutes or until water has been absorbed. Remove from heat. Stand, covered, for 10 minutes.
Transfer rice to a large ceramic dish. Using a spatula, stir rice to break up lumps. Gradually add seasoning, lifting and turning rice, until rice has cooled.
Place 1 nori sheet, shiny-side down, on a sushi mat. Using moist hands, spread one-quarter of the rice mixture over the nori sheet, leaving a 3cm-wide border around the edges. Place one-quarter of the avocado along the edge facing you. Top with one quarter each of the salmon, cucumber and carrot. Using the sushi mat, roll up firmly to enclose filling. Repeat with remaining nori, rice mixture, salmon and vegetables.
Slice each roll into 4 pieces. Wrap in plastic wrap.