Combine butter, 1/2 c oil, Tabasco, salt, and pepper in bowl. Add chicken, marinate, covered, in the refrigerator overnight.
Vinaigrette: Combine orange juice, mustard, sugar, salt and pepper and the remaining 1/4 c oil; set aside. Grill chicken over high heat, 3 inches from the heat source, 4-5 minutes per side or until cooked through. Combine the celery, carrots, radishes, and cucumber in the bowl with the vinaigrette. Divide among 4 plates, top each with a piece of chicken. Sprinkle with fresh parsley. Top with Bleu Cheese Dressing. Yield:16 Servings.