How to export a VMware ESXi 5 VM into a file to restore it later?

There are a number of ways to do this. The following is a non-exhaustive list:

1. Use WinSCP to copy it.

2. Use Veeam FastSCP to copy it.

3. Use Trilead VM Explorere to copy it.

4. Browse the datastore and copy it directly.

5. Etc., etc.

EDIT

In your question you state that you want to export the VM but what you're really asking is how you can get it onto temporary storage so that you can rebuild the host. I didn't include the OVF export option in my answer as ewwhite did in his answer, but that is in fact another way to accomplish this.

I prefer the OVF approach in some cases.

File -> Export -> Export OVF template

This is also detailed here: Move VMware ESXi VM to new datastore - preserve thin-provisioning