to delete the unclicked options would require hand coding.
you would need to code a loop that looked at each option to see if it was included in the form post or not, if it is not included in the form post, then it was checked so delete it.
it would be easier to show a list of options that had already been set for the product, and delete the ones that _are_ checked. you could do this using a dataAssist delete multiple records behavior.
use a recordset to show all the options fro the product from the productoptions table, add a check box to the page, use the ProductOptionID as the checked value. add a repeat region around the check box, then apply the delete multiple records behavior.