In order to show a data-only chart, you will need to hide the title, the legend and the axes:
radChart1.PlotArea.XAxis.Visible = ChartAxisVisibility.False;
radChart1.PlotArea.YAxis.Visible = ChartAxisVisibility.False;
Then you can adjust the PlotArea Margins
as per your requirements.
As for the performance, you should be fine with a single chart with a few hundred points. Still, the product was designed to be easily customizable and feature rich and it does not cope well with extremely busy charts or lots of charts in a window. It is targeted for casual situations which do not require a high performance solution. That said, whether you will be satisfied by the performance will depend on the number of charts and items. Please, make sure intelligent labels are switched off, as they bring a heavy performance penalty when the number of items increase. Actually, you may consider switching the labels off altogether for any chart exceeding 15-20 items (depending on the size).
the Telerik team