Hi Helene,
In order to remove the "Html Editor" title you need to set the "ShowChromeForNonAdmins" property, within your markup, to false or simply to remove that property, because it's set to false by default.
e.g.
<portal:PortalWebPartZone HeaderText="Left part zone" ID="leftWebPartZone" runat="server" Width="100%" ChromeTemplateFile="LeftColumn.htm" ShowChromeForNonAdmins="false">
<ZoneTemplate>
<MonoX:Editor runat="server" ID="editor1" />
</ZoneTemplate>
</portal:PortalWebPartZone>
There are two ways to delete the editors.
1. If the editor resides in your markup then you can close it through it's "Visible" property(please see the attached image) or to delete it from your markup.
2. When you add the editor dynamically and then go to the design mode, you have "close" and "delete" options(please see the attached image). "Close" option will hide the editor, but "delete" option will remove the editor from the page.