Peel oranges. Cut into 1/4-inch slices; quarter each orange slice. In a large salad bowl toss together orange slices, romaine, sweet pepper, onion, and almonds. Set aside.
Season chicken with salt and black pepper. In a large skillet heat oil. Cook and stir chicken in hot oil for 4 to 5 minutes or until no longer pink. Remove skillet from heat. Toss chicken with mixture in salad bowl. Divide salad among 4 dinner plates.
Stir orange juice and vinegar into the hot skillet, scraping up any brown bits in the skillet. Whisk in 1 tablespoon olive oil and the Dijon-style mustard. Serve salad with warm dressing. Season to taste with coarsely ground black pepper. Makes 4 servings.