Depending on what you’re working with, you can just add more vegetables. A few handfuls of wilted baby spinach will save a lot of things−it cooks down quickly and adds bulk to absorb some of that salt. Otherwise, a quick rinse under warm water can work miracles for a plate of too salty roasted carrots. Rinse, reseason (with no salt!), and put them back in the oven to rewarm. Anything that you boiled then salted (peas, green beans, asparagus, etc) can also be rinsed, rewarmed, and reseasoned.