Hyperion, the online magazine published by Contra Mundum Press, has devoted Volume VIII, Issue 2, July 18, 2013 to Szentkuthy (the full 326-page pdf version can be found here). More on some of these articles in separate posts. This is a treasure trove of articles about and excerpts from Szentkuthy's books. Highly recommended.
Contra Mundum Press has also devoted itself to translating most (if not all) of Szentkuthy's work. So far there has been two books released. Each of their publicity pages below contains many helpful links (some of which I'll duplicate here). I'm sure more links will be added to the second book as reviews are published:
Marginalia on Casanova
Towards the One and Only Metaphor
I've never gone beyond introductory notes on Casanova, something I intend to correct before the end of the year, but do check out the links provided on its publicity page.
I'm not sure what order I'll go in for more posts on Szentkuthy. Since I haven't finished Metaphor yet, I'll probably start with some of the articles about him in Hyperion. Regarding Towards the One and Only Metaphor, the introduction to the English translation release by Rainer J. Hanshe can be found at Asymptote and The Quarterly Conversation. My jottings on the introduction can be found here.
Since Metaphor is the recent release, I'll include a link to Asymptote's excerpt from the book. Hungarian Literature Online has two posts with excerpts as well. The first sample contains the first two 'entries' that are important in understanding what Szentkuthy is attempting to do with the book. Or at least what he says he is trying to do. The second sample helps round out the picture on what it's like to read the book.
Speaking of Hungarian Literature Online, they have plenty of helpful articles on Szentkuthy. All of their articles tagged with the author's name can be found here. Some posts you may want to check out are Outprousting Proust (an overview to his work), A Comedy of Ideas (about his first book, Prae), and two excerpts from his Recollections: one and two. Entry 25, in the second excerpt, focuses on Metaphor.
Besides his biography, Szentkuthy's Wikipedia entry includes a bibliography and additional links.