Table salt, while great for seasoning, is not good in large amounts for plants—or any of us, really. Using a ratio of three parts salt to one part water, dilute the salt until it's thoroughly dissolved, and pour it directly on the weeds you want gone. Be incredibly careful where you pour, especially if the weeds are close to plants you want to keep alive. Too much sodium can damage the root structure of surrounding plants.
Related: 9 Natural Ways to Kill Weeds