Once the rice is cooked, place it in a large bowl and let it cool down until it is warm. When there is no longer lots of steam coming off the rice, add the sushi vinegar to it and mix thoroughly.
Next, bring a pan of water to the boil on the stove and add in a teaspoon of salt. Once the water has boiled, add the shrimp, cover up the pan and then remove or turn off the heat.