Flavored simply and easily with ponzu sauce. You can gobble this up as a drinking appetizer too.
I tried adding cherry tomatoes to the usual marinated octopus. Ponzu is so versatile; I end up using it in a lot of dishes.
Be sure to chill well before serving. You could use the onion without soaking in water, but one time they were pretty harsh, so I soak them just in case. It could depend on the type of onion though.
Enjoy Japanese food around the world.