Rinse komatsuna with water, wrap in plastic wrap, and microwave at 600W for 1 minute. Rinse under cold water, squeeze out excess water, and cut into 4 cm pieces.

Place komatsuna in a tray and add mentsuyu, ensuring it is evenly soaked.

Crack the egg into a bowl, add sugar and cornstarch, and mix well.

Heat vegetable oil in a frying pan, add the egg mixture, and stir over medium heat until cooked through.

Wipe the frying pan clean with a paper towel. Add salmon, sake, and mirin, and bring to a boil over medium heat. Flip the salmon and cook until the color changes. Break the salmon apart, removing bones and skin, and cook until the liquid evaporates. Add salt, sesame oil, and sesame seeds, and stir to combine.