While I let the teacher use some trial and error to explore the features, if I didn't give them some clear directions about how to get started they would likely get frustrated and stop engaging.
What are you thoughts about teaching skills/how-to use things in a constructivist way?
I try and couch a teacher's experience within a constructivist environment. I don't approach them as teaching Moodle. I approach them as giving them a chance to improve classroom instruction, to improve web 2.0 student skills, to allow an online collaborative tool for their students (or whatever).
Within that parameter I make sure they the appropriate tools to learn the base skills. I have screencasts, step-by-steps, and documents.
However I think a teacher must know why they need to know something before they are taught how to learn it. Through a constructivist exercise, teachers approach basic Moodle techniques so that they know why they need to know.
I also make sure that there are appropriate collaborative tools in place to allow communication and dialog.
Instead of introducing a wiki, introduce collaborative writing. Why is collaborative writing of value? What does a student get out of it? What does a teacher get out of it? Then, how can Moodle facilitate it?
I once was working with Smalltalk/Squeak for my Swiki (long before Moodle), asking for a how to solution. Then THE Alan Key did not aswer my question but gave me a only a small piece of new information. I felt first then then , but realised after several hours how much better this small piece of information was then "the whole answer"
Read this several times and..