-FeatureLevelES2 should do the trick. The mobile preview from the editor also specifies -faketouches to make the mouse behave like touch events (not needed if your project has that globally set).
// apply additional settings
if (bPlayUsingMobilePreview)
{
AdditionalParameters += TEXT(" -featureleveles2 -faketouches");
}
Cheers,
Michael Noland