How are you adding the page field onto your markup? Through a view or as a pagefield?
If you're adding it as a pagefield add the attribute stripParagraph="true"
If you're adding in a view then you could try
Html.Raw(library.RemoveParagraphTags(Model.bodyText.ToString()))
But that will only remove the first one
You could roll your own version of that method to remove all P tage, or try what's suggested here - http://scottsdevblog.com/2011/08/get-rid-of-those-pesky-p-tags-in-umbracos-tinymce-editor/