how do i unstick caulk?
Answers:
Most likely he did this by accident, I can't see any good reason for caulking windows shut. I would however still call him and check with him before cutting them open. If he did have his reasons, he would probably just do it again and deduct whatever time and money you have cost him from your security deposit.
Other answers:
heat it up with a blow dryer
heat it up with a blow dryer
you might need to cut around the frame where it was caulked.
Use a razor blade to cut open the seam. The kind you buy that have a casing around the blade and are retractable.