Not that I know of. The page is anchored to the ruler (upper left corner of page at "0" on the ruler). Unless the ruler can be set to show negative numbers (and there's no indication that it can), then there's no way to change this.
Since there's no way to type outside the margins of the page in Wrap to Page, there's also no particular need to have the window wider than the page - just resize the window to match the dimensions of the page.
If you mean that you use both Wrap to Page and Full Screen mode... again, nothing you can do. Unless your page dimensions match the dimensions of your display, there's going to be gray space around the page, and the page is going to be positioned flush-left. I do understand why you'd want to be able to center; on my 27" iMac, you get this (seems pretty silly, doesn't it?):
View attachment 628972
Like the old joke goes, "Doctor, it hurts when I do this." "Then don't do that!" If you're taking an app to Full Screen in order to banish distractions... I can see how this would be more distracting than useful.
Full Screen definitely has its uses, but it tends to be more beneficial on a laptop or other small screen - when you're using a large display like mine, there are lots of apps that just don't work that well in Full Screen.
