How come the subject is I in this sentence?
"Chci" is 1st person sg.
I wonder how one might translate into Czech the English sentence: THAT I want to see! (emphasizing that I am interested in seeing that and not something else).
You can do that using "Já chci vidět TAMTO!"
What makes you decide that the czech "to" is the english that ond not this? In my opinion to does not imply one or the other but is neutral. So both should be accepted, this and that, im most cases
No, they should not. It is not neutral (except of the to je /je to construction), to=that, toto=this.