In a bowl, while cooked rice is still hot, mix with rice vinegar, toasted sesame seeds (optional) and about 2-3 tablespoons of sugar. Save the rest of the sugar for spam marinade. Set aside.
In a separate bowl, stir together soy sauce, oyster sauce, and remaining sugar until sugar is completely dissolved. Marinate cut spam in sauce for at least 5 minutes. Fry/cook spam for 2-3 minutes on each side.
Beat eggs and cook just like how you would cook scrambled eggs (add salt and pepper to taste). Cut cooked scrambled eggs in 1" strips.
Place Nori/seaweed sheet smooth/shiny side down. Place and spread a small amount of rice to a quarter of an inch thickness (about 3-4 tablespoons, we don't want to add too much as it might get too thick and difficult to roll). Make sure to leave about 2 inches of nori/seaweed sheet on the far end without rice to be able to seal it shut (by wetting it a little) after rolling.
Assemble other ingredients like cut spam, egg, cucumbers and/or carrots on top of the rice. Add a little bit of mayonnaise. Roll Nori making sure to apply pressure to tighten the roll. Use a bamboo mat with cling wrap on top to help with the rolling process.
To serve, cut each roll into eight pieces. Arrange sushi slices on platter. Decorate by squeezing mayonnaise on top. Chill and serve with dipping sauce.
