With your situation, there are choices to make, depending on your SAS programming preference, as follows:
1) A macro can be used to reference your findings in DICTIONARY.COLUMNS and generate the SAS statements as required for your PROC REPORT execution, or
2) you can also use SAS DATA step logic (again using the output of COLUMNS) to do PUT commands to a "TEMP" FILENAME allocation and then %INCLUDE that temporary file inline with your PROC REPORT code.
The SAS support http://support.sas.com/ website has SAS-hosted documentation and also supplemental technical/conference papers on this type of topic. A SEARCH facility is available at the website, and also you can consider using something like a Google advanced search (like the argument below):
generate sas code using dictionary columns site:sas.com
Some of the results I found for your interest are listed below: