Welcome to the Community,
ESXi is not an application which which gets installed on another OS. It is a bare metal Hypervisor, i.e. the operating system which is installed natively on the hardware. ESXi itself only requires ~1GB for the OS and another ~4GB for a scratch partition/location to store e.g. log files. The remaining disk space is used as a datastore on which you create the virtual machines. Rather than accessing disk space natively, create the virtual machines with virtual disks located on the datastore(s). To access the VM's - in addition to the ESXi tools, e.g. the vSphere Client - you can use any utility (like RDP) that you would also use to access the same OS on a physical systems.
André