I would agree with all of the points made so far.

1) you need to control the slugs first. Before doing anything else.

2) There is no pesticide you are going to "spray on".  Deadline is a slug bait; however, it is a dry granule, and needs to be spun on.

3) Some people swear by the use of water: liquid nitrogen.  You can try it.  Using a sprayer.  (But it is not a "pesticide".)

4) If you can get the slugs controlled, I would give the beans a couple of days to see if they leaf out.  You might find that you will lose some plants, and some plants will recover.  However, controlling the slugs is the first job.