Finely dicing something drives me a bit mad. I am not a fussy cook – I like things easy and simple. Maybe Cat can offer an easier/better method, but this one's mine. I'll use a zucchini as an example. Cut the zucchini in half, and then stand each half on its cut end. This gives it stability, making it easier to slice into ½-¾cm stalks/ribbons/long-thin-things. Now line your long-thin-things up and chop into ½-¾cm cubes. Voila. Easy.