Tropers / Anemotaxis
iPhone/iPod touch spoiler bookmarklet
Also see prescience's version of this bookmarklet
for showing and hiding all spoilers on a page.
iOS installation instructions
Follow this link
Now, when you're on a page with spoilers, open the bookmark you've made (the page will not reload), and tap spoiler sections to unhide and rehide them. Links inside spoilers will not be clickable unless the spoiler is visible first.
Note that this bookmarklet only works for regular spoilers, not super-secret spoilers.
You can try tapping a spoiler right here: This first sentence is a link. Tap it again to go to the wiki home page.