Prepare the Sushi Rice: Rinse the sushi rice under cold water until the water runs clear. Combine the rice and water in a medium saucepan, and bring to a boil. Once boiling, reduce the heat to low, cover, and simmer for 15 minutes. Remove from heat and let it sit for 10 minutes without lifting the lid.
Season the Rice: In a small bowl, mix the rice vinegar, sugar, and salt until dissolved. Fold the seasoning into the cooked rice gently using a wooden spoon, being careful not to mash the grains. Allow the rice to cool to room temperature.
Prepare the Cucumbers: Slice one cucumber in half lengthwise and scoop out the seeds using a spoon, creating a hollowed boat. Repeat with the second cucumber. Cut both cucumbers into thin strips (about 1/4 inch).
Assemble the Sushi Rolls: Place a sheet of nori, shiny side down, on a bamboo sushi mat. Wet your hands to prevent sticking and take about 1/4 of the sushi rice, spreading it evenly over the nori, leaving about an inch at the top edge.
Add Fillings: Place avocado slices and cucumber strips in a line across the rice at the bottom edge of the nori.
Roll the Sushi: Starting at the bottom edge, lift the bamboo mat and begin rolling away from you while applying gentle pressure to keep everything tight. Roll until the nori seals at the top edge. Repeat the process with the remaining ingredients to make more rolls.
Slice the Rolls: Using a sharp knife, wet the blade and slice each roll into 6-8 pieces. Wipe the knife with a wet cloth between cuts to ensure clean slices.
Serve: Arrange the sushi rolls on a platter and garnish with sesame seeds if desired. Serve with pickled ginger and soy sauce for dipping.
Notes
Serve the sushi rolls on a colorful plate with small dishes of soy sauce and pickled ginger. Add a sprinkle of sesame seeds over the rolls for an extra touch!