My Googlefu is letting me down so I was just wondering if the community knows of any similar resources for designers to hone their craft since I'm not really versed in that community?
I am not that familiar with the offerings of codecademy etc, but I tend to doubt that anything taught there can replace experience and serious study of algorithms and patterns. So while I suppose there could be a site teaching about fundamentals of composition, line, form, color, typography, etc, I'd think you'd be better off reading a book on those than anything else. Any exercise you would do would have to be evaluated algorithmically, which seems very hard judging by the subjective nature of design.
Like coding most growth in design happens through actually doing it. This means developing drawing skills, rapid prototyping skills, and most importantly your eye. I don't think any of this can be adequately taught through an interactive website. My suggestion to you would be to simply begin designing.
Hope that helps...
Whenever I start on a design I gather several reference layouts so my mind can think about how to best put things together.
Then get great feedback from other designers. I happen to have a lot of friends in the space that help me.
Check out http://www.thebestdesigns.com for inspiration.