Rinse the rice: Rinse the sushi rice under cold water until the water runs clear, then drain.
Cook the rice: In a pot, combine the rice and water. Bring to a boil, cover, and reduce the heat to low. Cook for about 15 minutes, then remove from heat and let it sit, covered, for 10 more minutes.
Season the rice: In a small bowl, mix the rice vinegar, sugar, and salt until dissolved. Gently fold this mixture into the cooked rice, then let it cool to room temperature.
Assemble the Sushi Rolls:
Lay out the nori: Place one sheet of nori on a bamboo sushi mat (shiny side down).
Add rice: Wet your fingers to prevent sticking, then spread a thin, even layer of rice over the nori, leaving a 1-inch border at the top.
Add fillings: Arrange a few slices of avocado and cucumber along the center of the rice.
Roll the sushi: Use the sushi mat to carefully roll the nori over the fillings, pressing firmly but gently. Wet the top border of the nori to seal the roll.
Slice: Use a sharp knife to slice the roll into 6-8 pieces.
Serve:
Arrange the sushi on a plate and serve with soy sauce, pickled ginger, and wasabi if desired.
Tips:
For a twist, try adding carrot strips, bell peppers, or tofu for extra flavor.
Keep a small bowl of water nearby to dip your fingers, preventing the rice from sticking.