1. Start by cooking your rice. Meanwhile make the sushi vinegar : In a cooking pot add vinegar, sugar and salt. Cook until almost boiled and sugar and salt are completely melted. Remove from the heat and set it aside.
2. Transfer the cooked rice into a heat-safe bowl, and pour the sushi vinegar from #1 on it. 'Slice' the rice with a rice paddle and let it cool down.
4. Spread about 180g sushi rice evenly. Leave an about 2cm edge uncovered.
5. Spread mayonnaise along the center line, as much as you want, over the rice. Place avocado, onion and salmon along that line too. Then roll up the maki tightly with a sushi rolling mat. Make 2 more sushi rolls.
6. Cut slices in the sushi roll with a clean and moistened knife. Please clean your knife before each new slice.