Check out this article that provides the following recommendations for cooking without salt:

The grated rind, or fresh squeezed juice of lemon is a zesty sodium alternative that has the added benefit of cutting fats and tenderizing meats.
A delicious lemon pepper seasoning can be made at home by combining dried lemon peel with red, white and black peppercorns and a pinch of cayenne, to taste. Sun dried tomatoes and some orange peel can also be added. Grind till fine in a spice grinder or food processor. Combine with toasted garlic and …