Firefox cannot run on the Windows "RT" operating system that is used on some tablets like the original Surface.

However, Firefox can run on the "full" Windows operating system used on more advanced tablets like Surface Pro.

Whether Firefox runs well on the tablet is a different question. The desktop version of Firefox is not a touch-optimized browser, for example, so I think it would work better with a trackpad or mouse than with a finger.

penguino said

I have a tablet with Windows 8.1, Intel Z3735F SoC and 2GB of RAM. Will it run Firefox without problems? Thanks.

http://ark.intel.com/products/80274/Intel-Atom-Processor-Z3735F-2M-Cache-up-to-1_83-GHz

I don't think 'Firefox for desktop' isn't going to run too well on an Atom processor, if it even will install on that device.