Is there a product that I can apply to outside of windows that face the beach that might deter sand, bugs,grit, etc., from sticking to the windows?
Maybe try something for auto windshields, like Rain-X?
On the beach you are under constant attack of the elements. Comes with the nice view.
Other than using a high quality window unit, there is little you can do to reduce the environments fury upon it. Rain-x is great against mineral build up (hard water stains ), but isn't going to provide much protection against wind driven moisture/rain against the side of a beach house. Because of the environment, you're going to have to be more vigilant with caulking and paint to keep the trim and siding in top shape, which, in turn, will facilitate the windows doing their job.
As dj1 points out, the view and the ambiance are well worth the added expense.