Heat oil in saucepan. Add red pepper flakes and cook over low heat for 1 minute. Add 4 chopped scallions; saute briefly, then remove from heat. Stir in brown sugar, rice wine vinegar, sesame oil, soy sauce, ginger, and garlic; mix thoroughly. Return pan to low heat. Add peanut butter a little at a time, stirring constantly. Add chicken broth, stirring constantly. Heat to piping hot. Place cooked fettucine in a large shallow bowl. Pour peanut sauce over and toss to combine. (If less sauce is desired, the excess sauce may be refrigerated and then reheated for other use.) Sprinkle with toasted peanuts and sliced scallions. Arrange cucumber slices in concentric circle around pasta. Arrange red pepper strips to radiate from center. Sprinkle coconut in middle of dish. Serve immediately. Makes 4 to 6 servings.