Combine Creole Seasoning and garlic in small bowl; mix well. Evenly coat beef Flat Iron Steak with mixture. Place steak in center of grid over medium, ash-covered coals. Grill steak, covered, 10 to 14 minutes for medium rare (145°F) to medium (160°F) doneness, turning occasionally. Remove from grill; let rest.
Meanwhile, combine chayote, tomatoes, parsley and vinegar in large bowl; mix well. Season with salt and pepper, as desired. Add greens, crabmeat, onion and 1/2 cup Cajun Remoulade Sauce; mixing gently but thoroughly.Cajun Remoulade Sauce: Combine 2/3 cup mayonnaise , 1/2 cup finely chopped roasted red bell pepper, 2 tablespoons thinly sliced green onion, 2 tablespoons Dijon-style mustard, 2 tablespoons fresh lemon juice, 2 tablespoons hot pepper sauce and 1 tablespoon chopped fresh parsley in small bowl and blend. This sauce may be made a day ahead, covered and refrigerated until ready to use.
Carve steak into bite-sized pieces; season with salt, as desired. Divide salad between 4 plates; top with steak and drizzle remaining Remoulade Sauce.
Nutrition information per serving: 538 Calories; 354.6 kcal Calories from fat; 39.4 g Total Fat; 8.8 g Saturated Fat; 0.5 g Trans Fat; 17.1 g Polyunsaturated Fat; 10.9 g Monounsaturated Fat; 147 mg Cholesterol; 1210 mg Sodium; 11 g Total Carbohydrate; 3.2 g Dietary Fiber; 33 g Protein; 4.1 mg Iron; 532 mg Potassium; 3.9 mg Niacin; 0.5 mg Vitamin B6; 5.1 mcg Vitamin B12; 8.4 mg Zinc; 47.8 mcg Selenium; 113.7 mg Choline;