How do I extract table items without column headers?

You can set the extraction area and the extraction columns to get the table items.

// Set extraction columns explicitly.
// Coordinates in CustomExtractionColumns must match the left edges of the columns.
// To get coordinates in PDF points you can use PDF Multitool application 
// installed with the SDK. It shows mouse cursor coodinates in PDF points in the toolbar.

extractor.CustomExtractionColumns = new double[] { 33, 111, 276, 312, 375, 449, 501, 547, 613, 687, 735 };
extractor.SetExtractionArea(33, 111, 723, 488);