How do I simulate a hover with a touch in touch enabled browsers?

OK, I’ve worked it out! It involves changing the CSS slightly and adding some JS.

Using jQuery to make it easy:

$(document).ready(function() {
    $('.hover').on('touchstart touchend', function(e) {
        e.preventDefault();
        $(this).toggleClass('hover_effect');
    });
});

In english: when you start or end a touch, turn the class hover_effect on or off.

Then, in your HTML, add a class hover to anything you want this to work with. In your CSS, replace any instance of:

element:hover {
    rule:properties;
}

with

element:hover, element.hover_effect {
    rule:properties;
}

And just for added usefulness, add this to your CSS as well:

.hover {
-webkit-user-select: none;
-webkit-touch-callout: none;        
}

To stop the browser asking you to copy/save/select the image or whatever.

Easy!