Veggie Sushi Rolls

Name: Veggie Sushi Rolls
Ingredients: cooked sushi rice 1 1/4 cups (6 oz/185 g); unseasoned rice vinegar 1 teaspoon; toasted nori seaweed 1 sheet, about 7 by 8 inches (18 by 20 cm); toasted sesame seeds 1 tablespoon, plus more for sprinkling; English cucumber 1/4, peeled and cut into thin matchsticks; carrot 1/2, peeled and cut into thin matchsticks; ripe avocado 1/4, thinly sliced; soy sauce and pickled ginger slices for serving (optional)