How to build a minimal WiX installer UI without a license page?

I would simply use one of the already created WiX UI and override the sequence (make it higher so that it will override the previous setting):

    <Product> 
        ...
        <UI>
            <UIRef Id="WixUI_InstallDir" />

            <!-- Skip license dialog -->
            <Publish Dialog="WelcomeDlg"
                     Control="Next"
                     Event="NewDialog"
                     Value="InstallDirDlg"
                     Order="2">1</Publish>
            <Publish Dialog="InstallDirDlg"
                     Control="Back"
                     Event="NewDialog"
                     Value="WelcomeDlg"
                     Order="2">1</Publish>
        </UI>

        <Property Id="WIXUI_INSTALLDIR" Value="INSTALLFOLDER" />
        ...
    </Product>