Any tips on optimizing a full javascript site?

Can search engine read the JS content, any extra coding needed to feed the spider...?

Yes and No. Google now able to render common JavaScript and also with the screen capture technology, Google is able to read the text inside the images (so far I know it works for English only) this is why Google acquired recaptcha years back. This also let Google understand your page layout to determine content positioning.

Again this is depending on your website...no one can give a definite answer to you.