XFCE transparent desktop icons:

File:
$HOME/.gtkrc-2.0

For black text:

style "xfdesktop-icon-view" {
    XfdesktopIconView::label-alpha = 0

    fg[NORMAL] = "#000000"
    fg[SELECTED] = "#000000"
    fg[ACTIVE] = "#000000"
}
widget_class "*XfdesktopIconView*" style "xfdesktop-icon-view"


For white text:

style "xfdesktop-icon-view" {
    XfdesktopIconView::label-alpha = 0

    fg[NORMAL] = "#ffffff"
    fg[SELECTED] = "#ffffff"
    fg[ACTIVE] = "#ffffff"
}
widget_class "*XfdesktopIconView*" style "xfdesktop-icon-view"