In a nonstick skillet, heat 1 1/2 teaspoons of the oil. Add the red onion and cook over moderate heat until softened, about 5 minutes. Add the turkey bacon and cook over moderately high heat, stirring, until browned, about 3 minutes. Add the spinach and tomatoes and cook until the spinach is wilted, about 2 minutes. Transfer to a bowl and season with salt. Wipe out the skillet.