Practice for publications in foreign language
I am personally not aware of any open online courses although I would be surprised if none existed. I can, however, point you to some other good resources. First there is the Purdue Online Writing Lab (OWL) which has guides and resources for teaching so it is not a course in itself but contains very useful material. I can also recommend a couple of books on writing in English for non-native English writers.
The first is

Robert A. Day and Nancy Sakaduski, 2011. Scientific English. A guide for scientists and other professionals. (publisher link)
Hilary Glasman-Deal, 2010. Science Research Writing For Non-Native Speakers Of English: A Guide for Non-Native Speakers of English. Imperial College Press (link from publisher page)

and then of course

William Struk Jr and E.B. White, (many editions over the years). The Elements of Style. Longman/Pearon. (publisher link)