In a mixing bowl, combine lemon juice, sugar, and salt. Add julienned carrots, cover, and refrigerate for 30 minutes.

Slice fresh cucumber into thin strips and sprinkle with salt. Let sit for 10 minutes; squeeze out excess moisture.

Beat eggs, heat cooking oil in a skillet, pour in eggs and cook for 2-3 minutes, rolling into a log, cool, and slice into strips.

In the same skillet, sauté sliced sausages and crab meat for 3-4 minutes until warmed and slightly crispy.

Combine warm rice with salt, sugar, black pepper, sesame oil, and sesame seeds. Ensure the rice is warm for rolling.

Lay a nori sheet shiny side down. Spread seasoned rice evenly, leaving a border. Layer with pickled carrots, cucumber, omelet strips, and cooked sausage and crab.

Starting from the bottom, gently roll the nori, pulling in the filling. Slice into bite-sized pieces and serve immediately.