In a large bowl, combine the cooked rice, sesame oil, and salt. Mix well and set aside.
In a small skillet, heat a little vegetable oil over medium heat. Pour in the beaten eggs and cook into a thin omelet. Remove from the skillet, let cool, and cut into thin strips.
In the same skillet, add more oil if needed and sauté the julienned carrots until tender. Set aside.
Sauté the julienned cucumber briefly in the same skillet. Set aside.
Place a sheet of nori on a bamboo mat, shiny side down.
Spread a thin layer of the seasoned rice over the nori, leaving about 1 inch at the top edge uncovered.
Arrange a few strips of each filling (carrot, cucumber, egg, spinach, fish cake or beef, and pickled radish) horizontally across the middle of the rice.
Using the bamboo mat, carefully roll the nori and rice over the fillings, pressing gently to keep everything together.
Continue rolling until you reach the uncovered edge. Rub a little water on the edge to seal the roll.
Using a sharp knife, cut the roll into bite-sized pieces.
Repeat with the remaining ingredients to make more rolls.
Enjoy your meal!