Korea has quite the interesting recent history. Try looking up the Yeosu incident too. One of the historical blogs, I believe it was Brian in Jeollanam has done detailed posts on that in the past. I'd check his archive lest he's covered Jeju too. I find with a lot of Korean history, your options to find stuff online in English can be limited, but there's museums in English at any major "incidental" site if you visit, and probably scholarly works or more formal history books you can dig up too.
On that note, even around whatever town you live in, keep an eye out for English plaques, hey. Local history is all around you everywhere in Korea, and a lot more is recorded in English than you'd think. Just tends to be poorly indexed.
Edit: An idea I had, perhaps put the call out to a Jeju resident to send some pamphlets or the like over to you from the local museum or photos of the plaques at the memorial park? I mean, your interest is on how it's taught, and how better to see that than see how they teach the locals about it? Jeju's touristy enough that a full translated copy of any material is likely a given.