Dual booting Ubuntu and windows 10 on Baytrail /2 gb /32 gb eMMC device

I have a Baytrail netbook with 2gb Ram and 32 gb eMMC storage comes with windows 10 32 bit preloaded .But i want to have an Ubuntu based 64 bit distro along with the default OS . I can’t completely replace it with Ubuntu since specs doesn’t allow 64 bit ubuntu to run smoothly as like win 10 (32bit ) does and manufacturer only support OS that comes preinstalled . How can i overcome the storage space , performance issue ? and help me to choose the correct Ubuntu flavor .