I used Jim's solution (thank you very much by the way, HUGE help there) and applied it to the default chart template.
In the palette area you have the resource dictionary for each line in the series.
Here is how I was able to get rid of it using Jim's control template, and I can put it in each ResourceDictonary so I don't have to do it line by line
<toolkit:ResourceDictionaryCollection>
<ResourceDictionary>
<!-- I wanted a solid color brush so I just went ahead and defined it in the palette-->
<SolidColorBrush x:Key="Background" Color="Green"/>
<Style x:Key="DataPointStyle" TargetType="Control">
<Setter Property="Background" Value="{StaticResource Background}"/>
<!-- below is where I entered Jim's control template into the default palette defined-->
<Setter Property="Template">
<ControlTemplate TargetType="charting:LineDataPoint">
<Grid x:Name="Root" Opacity="1"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
</toolkit:ResourceDictionaryCollection>
This worked for me at least, and it will save me a lot of time (and has already saved a lot of my hair before I pulled it out)