Using Rainbow Chard for Spanakopita Just for giggles I am planning to make spanakopita using rainbow chard instead of spinach. It's been years since I've worked with chard, so I have forgotten how it behaves. If I were using spinach I would steam it until it wilted and volume was reduced by half. Then I would chop it and wring the hell out of it with a tea towel. I wouldn't use any stalk that extended beyond the leaves. I want to use more of the stalk of the chard, because that's where most of the color is.

So, will treating the chard leaves like spinach be enough to dry it out for spanakopita? Keeping the bottom layer of filo crisp is paramount. Is there anything more I should do? Concerning the stalks, I'm thinking that I want to dice them fairly small, salt and drain them, steam them until tender, and then wring them with the leaves. Does that sound like the best way to handle them? Is there anything I should do differently? 

The color of the chard is the whole reason for this little endeavor. Is there anything I can do to help keep the color bright?

Finally, the flavors in my traditional spanakopita include parmesan, feta, yoghurt, lemon, dill, mint and nutmeg. Is there any reason to consider different flavorings with the chard instead of spinach?
Chard isn't as tender as spinach and will require more than just light steaming lest it be chewy and fibrous.

You said you want to keep its bright colors, so I would recommend blanching it in salt water. You need to add quite a bit of salt, such that it tastes like seawater. This keeps plant cells from bursting and releasing pigment. You can rinse your chard after pouring it off to tame saltiness.