Dice the tomato into 1cm cubes. Chop the mizuna into bite-sized pieces.

Place the glass noodles in a microwave-safe container and add enough water to submerge them. Cover loosely with plastic wrap and microwave at 600W for 5 minutes. Rinse in cold water, drain, and cut into manageable lengths.

In a bowl, mix all the seasonings (sugar, vinegar, soy sauce, sesame oil, sesame seeds, and chili oil).