How do you detect a Grid click/tap?

In the WP world aGrid/Border etc can detect when it is clicked/tapped event - ideal for light dismiss etc.
consider the following example, what is the best way to capture the grid _bgLightDismiss _being tapped

 <Grid>
                <Grid x:Name="bgLightDismiss" BackgroundColor="{x:Static theme:LightDismiss.BackgroundColour}" Opacity="{x:Static theme:LightDismiss.Opacity}" />
        <Frame BackgroundColor="{x:Static theme:Popup.BackgroundColour}" HorizontalOptions="Center" VerticalOptions="Center" >
          <StackLayout>

            <Label  Text="{Binding Text, Mode=OneWay}" TextColor="{x:Static theme:Popup.TextColour}" BindingContext="{x:Reference thisPopup}" />
          </StackLayout>
        </Frame>
    </Grid>