Unless you eat it raw it's impossible not to get smaller because squid loses a lot of water during the heating process, so it gets smaller.

So you can only try to pay more attention when processing, shorten the heating time. Specific points are:

First blanch quickly with boiling water, and then immediately fry a few times with rapid fire and then out of the pan. I suggest that before you fry a variety of seasonings, soy sauce, salt, monosodium glutamate, what are first ready, it is best to be adjusted in a small bowl. This can shorten a lot of time, do not have to put one after another.