Short answer, yes, absolutely. Salt, whilst it may kill slugs, also kills absolutely everything else, including plants, plant roots and a range of bio diverse organisms in the soil which keep the soil fertile and supply nutrients for plants to grow. If you've used salt, you will just have to wait for the toxicity level to fall - you can try regular and frequent irrigation to try to wash it away quicker, but essentially, you've poisoned the soil and it will take time for the situation to change and stabilise. There is nothing you can add to offset it; how long it will take for the salt toxicity to wash away is hard to say - it depends how much you've used, how free draining your soil is and how much water you can flush it with. If you thought you were being organic by using salt instead of metaldehyde pellets, you'd have been better off using the pellets.

Salt should never be used, even in small amounts, on areas where you want things to grow. I'd go further and say it should never be used in any way at all outdoors - even if its just used to kill weeds in cracks in paving, its possible for the salt to leach into other areas and cause problems.

Calcium helps break the sodium ions free of the soil quicker. I would use limestone powder in acid soils, or gypsum in alkaline. Water deeply after applying. If you are growing acid lovers, go ahead and use gypsum whatever the soil pH, or apply dilute vinegar solution a day or two after applying limestone.