Aside from the dressing, the only other required ingredient is cucumber. I like using Japanese cucumbers for their texture, vibrant color, and lack of seeds. If you can't find Japanese cucumbers, other thin-skinned cucumbers such as Lebanese or Persian ones are suitable substitutes. If you can't find those either, Hothouse (a.k.a. English) cucumbers will work in a pinch, but you'll want to cut it in half lengthwise and scrape out the seeds before slicing it. Beyond cucumber, most people also include wakame, which is a type seaweed. It usually comes dried or salted and needs to be rinsed and rehydrated in cold water for a few minutes before being used. Once rehydrated wakame should look like thin frilly sheets of dark green paper. To give the salad a bit more substance, I like to add some cooked seafood such as shrimp, crab, or octopus. You can also get a little creative here and add other proteins such as shredded chicken breast or edamame.