Sea beans are one of those things - like many kinds of berries or mushrooms, like ramps, even like some cuts of beef - which are commonplace and cheap for 5% of the population, expensive and rare or unheard-of for the rest. Unlike strawberries, which can be grown big and styrofoamish and trucked across the country, huckleberries or sour cherries are too fragile for commercial freight; ramps, sea beans, and many black raspberries grow wild and are foraged rather than being raised commercially. Sea beans, like many of these things, have the additional expense-adding strike that they are somewhat perishable - while they won't go bad in refrigeration very quickly, they won't retain their texture as long.
They are normally bigger than what I have here - these are "micro sea beans," especially small and tender ones.
So you have the people who can simply walk outside and forage them for free, or pay a token amount to someone who's already done so, and can't imagine paying premium prices for them nor why they would show up on the menus of "gourmet restaurants." And you have the big middle, who's never heard of them. And you have the small percentage of people, probably about as big as the first group, who love them but don't have access to them, and are sometimes willing to pay that premium.
The reason sea beans are available in such a small part of the world is made pretty obvious by the name: they grow by the sea (or salt marshes), especially in the north. While "sea bean" sometimes means "drift seeds," in edible contexts we're talking about species of salicornia, sometimes called samphire, glasswort, or pickleweed. The "bean" they resemble is the string bean, not the shell bean, and they have a snappy crisp texture similar to haricots verts.
I love them. They're crisp, they're salty - the full-size sea beans can be too salty - and they have a slight marine flavor like seaweed, but not as pronounced. The combination brings up a thousand memories and associations, mainly with the ocean near my grandparents' house when I was a kid. I never had sea beans there, but the taste is a lot like the smell of being at the beach.
For lunch I'm just having them as an accent - more than a garnish - with ddukbokki:
Ddukbokki is just Korean ricecakes - dduk - with hot sauce. "Ricecakes" is a misleading term in American English - they're thick, chewy, nearly-neutral-flavored dumplings made from sweet rice flour, which soak up whatever flavors are around them (in this case a punishingly hot pepper paste). I'll have a post more specifically about them at another time - they're terrific with chili.