Preheat oven to 375 degrees F. Heat oil in a 10-inch nonstick skillet over medium heat. Cook the sausage, crumbling with the back of a wooden spoon, until no longer pink, about 3 to 4 minutes. Add the scallions, season with 1/4 teaspoon salt and cook, stirring, until the scallions begin to wilt, about 2 to 3 minutes. Add bell pepper, and cook, stirring until wilted but not completely limp, about 8 to 10 minutes.