Thinly slice the onions about 1/8-inch thick. In a soup pot, heat the oil over medium high heat. Add the onions and sauté for 8 to 10 minutes, stirring often, until very soft and just starting to become light brown on the bottom layer.
Reduce to medium-low heat and stir in the salt. Cook for 40 to 45 minutes, stirring every 5 to 10 minutes and adjusting the heat so they cook slowly without burning. The onions will change from raw to golden to light brown to very dark brown. Remove and set aside
Cook the bacon over medium heat, turning occasionally, until cooked. Crumble bacon into bits.