It really depends, and you should really check. I went to Israel for a week for business meetings, and needed a work visa. Coming from the US, I didn't need to file paperwork ahead of time, but coming from some other non-US branches I may have needed a letter of invitation from the local branch to do a business meeting and then leave.

Yes you can come in on a tourist visa and work, and I'm sure some people do that, but if you're looking to be on the full up and up, even short stays may need work visas.