WIQL for empty Tags...
SELECT
[System.Id],
[System.WorkItemType],
[System.Title],
[System.State],
[System.AreaPath],
[System.IterationPath]
FROM workitems
WHERE
[System.TeamProject] = @project
AND Tags NOT CONTAINS '#'
AND System.AssignedTo = 'Shawn Cicoria'
ORDER BY [System.ChangedDate] DESC