In a 2002 New York Times best-seller called Salt- A World History, the author Mark Kurlansky informs us that salt is more than the simple food additive that appears on our tables. He documents that wars have been fought over it; it has been used as currency; governements have been formed and have fallen because of it; and it has been one of the most valuable and sought-after commodities the world has ever seen. The ancient Chinese, Egyptians, and Celts were some of the peoples of history who developed methods to produce salt and to bring it to market. Today, salt is one of the newer gourmet products available. You can get Himalayan Pink Salt, Grey Sea Salt from France, and Hawaiian Red Salt. The color, characteristics, shape, and flavor depend on the area in which it is harvested. Kosher salt is one of the most popular of the gourmet salts on the market due to its coarseness and texture. What does salt have to do with Vayikra?
In Perek Beis, Pasuk yud gimel, the Torah says, Al kol korbankha takriv melach. All of the sacrifices had to be seasoned with salt. V'lo tashbis melach bris Elokekha. G-d's Covenant of Salt shall not cease from your offering. Rashi explains that the covenant relating to salt goes back to Creation. On day 2, G-d split the upper waters from the lower waters. The lower waters complained that they were far away from G-d while the upper waters were closer. In respone G-d said not to worry. The lower waters from the oceans will be used as a libation upon the altar and will rise heavenward each day. The salt in the ocean would also be used to season the offerings.
In commentaries there are three approaches to understanding the presence of salt on the altar. First, salt adds flavor; not that G-d has to "taste" the offering, but in human terms we present to G-d that which is palatable to us. Second, salt functions as a preservative. On the altar, the salt serves to preserve the covenant between G-d and Israel. Third, salt enhances the natural flavor of food. When we taste salt on our tongues, our tase buds get stimulated so that we taste in a more intense way the flavor of the food we are eating at that moment.
This explanation can be applied in the context of our service of G-d. All of us have natural abilities according to our particular leanings. Adding "spiritual salt" we will enhance our natural characteristics. On Shabbat we commemorate this practice by adding salt to our challah, becasue our table becomes an altar to G-d. Let's stimulate our spiritual qualities, and may our service always be pleasing in the sight of G-d.