Restore Firefox to its Default Settings.

How do I restore it to default settings on my iPad.

Did you try deleting the app and downloading a fresh copy?

Yes I tried that and it still defaults to the desktop site.

In playing around with this, I found my iPad opening pages in desktop mode as you describe. The weird thing is I fixed the problem, but I'm not sure how. :)

At one point, I thought I noticed a difference when I held the iPad in vertical (as opposed to landscape) mode. Try holding yours vertcally and opening a page. If you need to, switch to mobile mode. Now close Firefox. Open again in vertical mode and see what happens. If it opens in mobile mode, does it change when you move the iPad to a horizontal positiion?

No it doesn't change