Rinse sushi rice and cook the rice with the same amount of water in a rice cooker.
In a small bowl, combine 1 tbsp rice vinegar, ½ tbsp sugar, and a small pinch of salt. Stir well to ensure everything is thoroughly mixed. (Microwave or heat the mixture in a small saucepan over low heat until the sugar and salt dissolve completely)
Once the rice is cooked, transfer it to a large plate or a shallow container.
Gradually pour the vinegar mixture over the rice while using a spatula to gently fold and mix. Be careful not to smash the rice grains. Continue adding the vinegar mixture until the rice is evenly coated.
Cool the rice with a fan or a piece of cardboard to help cool it down. This will give the rice its characteristic glossy sheen and sticky texture.
Assemble Chirashi Sushi
Prepare the toppings by chopping the spring onion greens, slicing the cucumbers, making an egg omelette and cutting it into cubes, and slicing the assorted sashimi into bite-sized pieces.
Spread the cooled vinegared rice evenly in a bento box or a sushi platter.
Arrange the prepared toppings over the rice. Add flying fish roe (Masago caviar), Hello Kitty fish chips or any other favorite toppings for a creative touch.
Serve the chirashi sushi immediately and enjoy the vibrant and delightful flavors of this easy-to-make Japanese dish!