In short, our adrenal glands are our stress regulators. Salt cravings are signs of adrenal stress. It is important to properly sourish the adrenal grands without giving into their salty needs. Good foods for adrenal support include: spinach, celery, carrots, beets, peppers, broccoli, Brussel sprouts, oranges, strawberries, mushrooms, eggs, soy, and lecithin (a supplement found at most health food stores)... with the best being the eggs, soy, and vitamin C-rich fruits and veggies.
Also, natural sources of salt include beets (who knew a vegetable was naturally salty?) and beet greens, sea veggies (think nori wrapped around sushi, dulse, seaweed, etc), and whey (found in yogurts, cottage cheese, dairy milks, and you can buy pure whey in protein powder forms).
If you find yourself craving excess salt, consider the sources of stress in your life. (However, you may also have a kidney deficiency according to TCM :P). Please talk to your health care provider about the state of your adrenals if you are concerned!