Yes I grew the Kin Tsai, and indeed it's noted for Asian cuisine especially Thai. Very easy to grow, but nothing like cilantro, it really tastes like celery (and it is a type of celery, for sure). It also didn't bolt in the first year, but quickly went to seed in the spring after overwintering.
The other herb often said to taste like celery is Lovage - IMO it is very different, you can call it 'similar' but really not very. That is a perennial, also very easy to grow.
Kath may tell you more about preserving celery, I've read you can both freeze and dry it. I actually pulled my plants for the seed very late in the season and dried the seed on the plant. The stalks on the flowering plant are on the woody side and wouldn't be considered good eating fresh, but they sure smell like celery and some of them dried a really nice green, so when i processed the seed I also put away some of the dry sticks to use in bouquet garni. I've used them to flavour soup and seemed to work fine, but of course the stick itself was not edible. I did also powder some of the green sticks and used some in savory muffins, believe it or not... but I can't tell they are there.
We used some of the seed on oven roasted potatoes, very nice.