Place the rice in a medium saucepan and bring to the boil. Cover the saucepan and cook for 15 minutes on very low heat. Turn off the heat and allow to stand 10 minutes covered. Transfer the rice into a large bowl. Mix together the vinegar, sugar and salt until the sugar dissolves, then drizzle over the rice. Mix together gently to coat the rice with the sushi vinegar; set aside to cool to room temperature.
Toast each nori sheet very lightly. Place a nori sheet on your rolling mat and spread 1 cup of cooked sushi rice evenly over the nori by pressing with wet fingertips. Cover another rolling mat with Glad wrap, place on top of rice and turn upside down to transfer.
Place avocado strips, salmon strips and crab meat together on top of nori and roll squizzing together gently. Cut into eight slices. Repeat for each nori sheet. Top with Osetra Black Caviar before serving.