Place a sheet of nori vertically on your bamboo rolling mat, rough side facing up.
Lightly wet your fingertips and spread ¾ cup / 150 g (5.3 oz) of sushi rice evenly over the bottom three-quarters of the nori sheet.
Sprinkle ½ teaspoon of toasted sesame seeds and a quarter of the sliced green onions over the rice.
Arrange 2 pieces of pickled okra end-to-end across the center of the rice. Lay a quarter of the carrot and red bell pepper matchsticks in neat lines next to the okra, followed by 1 tablespoon (15 ml / 0.5 fl oz) of corn.
Slide your thumbs under the mat and use your other fingers to hold the fillings in place.
Roll the bottom edge of the mat up and over the fillings, tucking them in tightly to start the roll.
Continue rolling, lifting the edge of the mat as you go, until the roll is sealed with the seam facing down.
Gently press the top and sides of the roll with the mat to create a firm, even shape.
Transfer the roll to a cutting board and let it rest seam-side down for at least 2 minutes.
Repeat the process to make three more rolls.
Dip the blade of a very sharp knife in water and use a gentle sawing motion to cut each roll into 5 equal pieces.
Serve immediately.
Keep a small bowl of water nearby to dip your fingers in (tezu) to prevent the rice from sticking to them.
Don't overfill your roll. It makes rolling much more difficult and can cause the nori to tear.