The SAR-EDU website set up by Friedrich-Schiller University Jena and the German Aerospace Center (DLR), provides lessons, talks, and tutorials (sample data included) for a range of radar remote sensing topics. Topics cover a broad range of processing & applications, from basic mathematics to general and application-specific image processing. Some units cover the use of programming (e.g. Python) and specific software (e.g. ESA's NEST). All of this is available for free, though registration is required.
There is a Biosphere category which includes a unit on crop type classification. If you don't find exactly what you need there I'm sure you will still find this to be a valuable resource.