A lot depends on why you are reducing the salt content.
If you are just looking to reduce your sodium chloride intake - simply use less salt! And, shy away from prepared foods where possible. Also look at the sodium content on the labels - some foods are brined or preserved with salt (sausages, wieners, some lunch meats, etc.) and consume them in smaller quantities or less frequently. All food grown in the soil, or consumes food grown in the soil, will contain some sodium chloride.
Unless there is a contraindication because of certain medications - dry wines will also trick the taste buds and provide a salty taste without added salt.
Of course - acids, like vinegars and citric acid, and herbs can be used as replacements.
Regarding commercial salt substitutes - most of these are Potassium Chloride. Potassium Chloride (KCl) isn't without it's problems - while it is used as a food preservative (as well as a part of the lethal injection in executions) and a substitute for common table salt (NaCl) in some instances - it isn't always a healthy substitute for sodium chloride (NaCl) - or common table salt, Kosher salt, sea salt, etc.
IMHO - nobody should just cut NaCl from their diet, or do a wholesale sub of KCl for NaCl, without talking to their physician first. Doing so can be lethal in some instances! Low sodium levels can screw up cell functions, cardiac functions, and brain functions.
We've had similar discussions in our Health, Nutrition and Special Diets Forum in the past.