Thoroughly rinse and tear spinach into large bowl. Heat 1 teaspoon oil in heavy large skillet over medium heat. Remove sausage meat from casings, add to skillet and saute until browned. Transfer sausages to paper towels using slotted spoon. Heat drippings in skillet over medium heat. Add green onions and stir 1 minute. Add vinegar and bring to boil, scraping up any browned bits. Mix in 1 tablespoon oil, mustard and orange juice. Add sausage and toss to coat. Season with salt and pepper, if necessary. Cool to lukewarm. Toss with spinach.