Rinse your rice until the water is clear
Boil 1/3 cup water (or whatever your rice package says) in a small pot, and add in your sugar, rice vinegar, and salt
Add in your rice, cover, and set to medium-low for 10-15 minutes, or until cooked. Your rice should be sticky and obviously not hard. Let your rice cool for a few minutes before adding it to your nori sheet.
Cut up your avocado into two strips and your cucumber into small matchstick strips.
Place your Nori Sheet on your sushi roller or a flat surface, and spread your rice out evenly until all the green is covered. Try not to have clumped areas of rice.
Add in your shrimp and avocado in the middle of your roll. Place your cucumber on top of your shrimp and avocado.
Roll your sushi. If you're using a sushi roller, this will be easy. If you don't have one grab the edge of your Nori and gently wrap your shrimp & avocado pile. Form the rice around your filling before rolling it over in your cylinder shape.
Wait until your nori is cool before cutting into pieces
If you're making the siracha mayo sauce, combine both in a bowl and drizzle over your roll once cut.
Congratulation, you did the sushi!