There are two large decks at HND
, both in the main terminal (on the 8th floor I believe). Both have views out over the main part of the field and two out of the three runways. The deck on the right hand side of the terminal has an upper level which allows views of the bayside runway and some of the remote parking stands. The decks are open from about 8am until late at night.
On the floor below the decks are a few restaurants which also give views over the field, although I haven't tried these restaurants myself.
There is also a new terminal currently being built, but I'm not sure whether this will have a deck.
Please let me know if you require any further information.