that is what I am doing as well.
Plus I have a workflow for viewing those files and I use it on the webportal. It is quite easy, it lists me all *.csv files on the server, I select one and on the next page I see the file.
It helps me quickly see the file. You can for sure enrich this to allow edits and write back to the server as well.
I think you cannot open the file directly in Knime
(at least I do not know of a file editor view in KNIME similiar to the eclipse one).
I think you would need to either create a view file web portal workflow like Iris is using
Use the file upload node to just download the file after the file is created
Or nagivate in the server directly e.g. through WINScp or other clients…