Polarizer would be nice for beach shots, but if you need to cut a lot of light, you would need an ND filter. They come in different strengths but act like a sunglass basically. They are usually a bit stronger than a polarizer even with one of the weaker ND filters but won't effect the color or reflections like a polarizer will.
As for wide angle, you would need something starting around a 10mm or 12mm. I used to have a Tokina 12-24mm which was great for stuff like that. I now have a Tokina 16mm-50mm but the 16mm is still pretty wide. So I sold the other lens and got this one because it serves more purpose with other shooting as well.