Rinse the sushi rice under cold water until clear, then soak for 30 minutes. Cook according to manufacturer's instructions with konbu.

Combine rice vinegar, sugar, and salt in a saucepan and heat until dissolved.

Whisk eggs in a bowl, then cook in a non-stick pan to form a thin omelet. Shape once cooled using cookie cutters.

Fold the sushi vinegar mixture into the cooked sushi rice and let it cool slightly.

Form balls using cling wrap, placing a topping in the center before shaping.

Decorate the balls with the shaped omelets and nori using mayonnaise to help stick.

Serve on a platter with soy sauce, mayonnaise, and wasabi on the side.