Yes, you can using CSS style properties. Just add a css style that specifies the width. Example:
In the above tag, the width of the select will be exactly 300 pixels regardless of the width of the text in any of the options. Be aware that this could cause some options to be truncated if they won't fit within 300 pixels.
To my knowledge there is no way to wrap options. Your choices are either to let the width grow to the size of the largest option (the default) or to set a width and accept the fact that options larger than the specified width will be truncated.
