Add the following to your form:
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
FormBorderStyle = FormBorderStyle.None; // hide the form border
Bounds = Screen.FromControl(this).Bounds; // make the form as big as the screen
}
As for making touchscreen applications: just make sure your buttons and other display elements are big enough to be touched with a finger without touching other nearby controls ! 