The water retain from occasionaly eating salty foods temporary. If you step on the scale every day, it can be very frightening. (For example after my favorite smoked salmon plate usually I have 3-5 lbs water gain. ) BUT this water goes away in 24-36 hours.
To eat salty/high sodium meals every day could cause hig blood pressure and other problems, so you should be careful if you have "salty tooth".