How can I achieve large bubbles in my bread?
In order to get large bubbles like you see in a Ciabatta you want to knead your bread as little as possible. Literally I mean knead it till just smooth but no longer. You really don't want to stretch any of the gluten. The more you stretch it the stronger it gets which is not what you want when trying to create nice UN-even air pockets.

On top of this, you DO NOT want to be knocking it back at all. I tend to prove my Ciabatta style bread on what ever I intend on cooking it on. That way I don't risk over handling it. 

Also you want to let it gently prove, at room temperature. No hot box or heat lamps at all.