If your LV's don't take up all the SSD PV space yet: connect a USB disk, make a partition on it and use is as a LVM PV, then add it to your volume group, and pvmove everything from the SSD PV. Remove the SSD PV from the volume group, make the SSD partition smaller, add it to the VG again, and pvmove everything from the usb disk. Remove the USB PV from the volume group, and you're done. The operation won't be incredibly fast I'm afraid, but it'll free up some space on your SSD.