While squash is roasting, in a medium saucepan combine remaining oil, remaining salt, oregano, red pepper flakes, and garlic. Increase heat to medium-high and sauté for 1 minute, stirring frequently. Stir in tomatoes with juices; increase heat to a boil. After 30 seconds reduce heat and simmer for 15 minutes, stirring every few minutes. Add balsamic vinegar, stir for an additional minute, and remove from heat. Taste and add salt, if necessary.