Like this:
Code:
INSERT INTO DestinationTable ( [Fiscal Year], [unique ID] )
SELECT SourceTable1.[Fiscal Year], SourceTable2.[unique ID]
FROM SourceTable1 INNER JOIN
SourceTable2 ON SourceTable1.[Employee Number] = SourceTable2.[Employee Number];
Use a LEFT JOIN if you want to keep Null values for the rows (if any) where there is no match for [Employee Number] between both table.
Note: You should refrain from using spaces (or other non-alphanumeric characters as well as reserved words) in the names and replace them with an underscore:
"
Fiscal_Year" instead of "
Fiscal Year"