Eating salt is the kind meant for cooking and eating. It's table salt.

This word is a jukugo that uses the on'yomi reading for the kanji, but you haven't learned the on'yomi reading for 塩 yet, so here's a mnemonic to help you:

Back in the day, you were only allowed to use table salt at the end (えん) of the meal. It was precious commodity, so to discourage people from using too much of it you could only use it at the very end of the meal.