In general, all the files generated for your project serve a purpose of some sort based on the diagrams and nodes you are using. I don't know of any special option to reduce the size of the project without changing something you are actually doing in your flow. My first suggestion is to look in the workspace folders of your project and see which files are large, giving you an indication of where you might be able to reduce the size of your project. For example, if you are partitioning the same data in multiple places then you will be creating multiple copies of your data. If you are using a SAS Code node, if you are creating new data sets instead of views then you are obviously increasing your project size.
If you send more details about your project we can help identify ways you might be able to reduce the project size.