First things first, pickle your cucumbers. I have a guide to pickling vegetables right here. You should do this a few hours before you plan to make this. I suggest using rice vinegar if you can, or white vinegar if you can’t. Hard (or soft) boil your eggs and let them cool. I personally think a jammy egg works best.
Combine your beef with the sake, mirin, soy, and ginger paste. It should be a little soupy. Don’t worry; it’ll cook off.
Cut up your scallions (white and green parts) and set aside. Make sure you’re cutting them big enough to be handled by chopsticks. I also like to cut mine on the diagonal.
Cut red onions into strips.
Wash and cook your sushi rice. Seriously. Wash that shit.
Cook your beef until it’s crumbly and the liquids have soaked in/evaporated. Don’t let it crumble into too small of chunks.
See above for tips and substitutions.