Grate the beets and eggs on a fine grater.
Cut the onion into rings.
Mash the sardines with a fork.
Finely chop the seaweed.
Lay out the salad in layers:
- sardines
- green onion
- mayonnaise
- sea kale
- egg
- mayonnaise
- beet
Let the salad soak for a couple of hours.
Before serving, decorate as desired.