Tapa is the term used to refer to salted, then dried meat. The meat may either be cured or uncured.
Cured tapa uses salitre or saltpeter. This gives the meat it's red color. Saltpeter, a common ingredient found in commercially cured meats, is used for food preservation... not really a very appetizing additive to put in your food especially once you find out it's other uses. See Wikipedia.com for more information on saltpeter.