Yeah, you don't want to use u Block for that unless you really know what you're doing. Element Zapper is meant to block the types of containers they put ads and other "content" in, not block specific listings. It can be done if you know how to identify the ID used for each specific job opening, but it doesn't sound like you do so I'd avoid that route.
Sorry, I don't have a recommended method of accomplishing what you want off the top of my head as I fortunately haven't really needed to seriously job hunt recently (just the occasional window-shopping). I just wanted to warn you against that particular method if you don't know what you're doing.