Wash peppers, remove stems, ribs and seeds. Cut into 1 inch wide strips.
Heat oil in skillet large enough to hold peppers. Add garlic, and cook until browned. Discard garlic. Add onions to the oil and cook until softened but into browned. Add the peppers and salt to taste, cover the pan, and continue to cook over low heat until the peppers are soft. (about 30 minutes)
Prick the sausages all over with the tip of a sharp knife. Put in one layer in a heavy frying pan with 2 Tbl water. Cook over medium heat heat, turning often. The water should evaporate and the fat should run so the sausage cooks in it's own juice. Cook until the sausage is browned, and cooked through (10 to 15 minutes).
Add the peppers and onions to the sausages and heat together 5 minutes.
*At most street fairs, sausages and peppers are served inside crusty Italian rolls, cut open to hold them.