PopupBehavior allows you to easily display a popup on a tap or right click.
In your view you should specify a template for your popup:
<TextBlock Text="Tap or right click here for more information" behaviors:PopupBehavior.Placement="Above">
<behaviors:PopupBehavior.Content>
<DataTemplate>
<TextBlock Text="More information..."/>
</DataTemplate>
</behaviors:PopupBehavior.Content>
</TextBlock>