No final, encontrei alguns artigos e escrevi o seguinte roteiro de Powershell - Você dá o nome do servidor - que deve ser um arquivo RDP já existente
$RDPFile=$Args[0]
Add-Type -AssemblyName System.Windows.Forms
$Screens = [System.Windows.Forms.Screen]::AllScreens
# Look for a non-primary screen - @todo - what if I have three screens?
$Screen = $Screens | where-object {$_.Primary -eq $FALSE}[0]
# If we dont have a screen which is not a Primary then use the primary
if ($Screen -eq $Null) {
$Screen = $Screens | where-object {$_.Primary -eq $TRUE}[0]
}
# Now connect using an RDP file - but set the width and height and full screen mode
mstsc.exe E:\cmds\RDP\$($RDPFILE).RDP /f /w:$($Screen.Bounds.Width) /h:$($Screen.Bounds.Height)