Capture all Data from Single Column?

I have a .xslx with 20,000 rows and multiple columns. Row 0 has the 'column
names'. I want to find the column named 'Supersize' and then get all of the
row-data below that column only into a List<>.

I am using the Open XML SDK to create an instance of a SpreadsheetDocument
of the file, and I think I get a proper instance of Sheet and WorksheetPart.
But now I am stuck. Can I use LINQ or something similar to get all of the
column values I need?

Help, desperate!

Thanks.
.