Combine coriander and cumin; press evenly onto beef steaks.
Place steaks in center of grid over medium, ash-covered coals; arrange watermelon slices around steak. Grill steaks, covered, 10 to 14 minutes (over medium heat on preheated gas grill, 11 to 15 minutes) for medium rare (145°F) to medium (160°F) doneness, turning occasionally. Grill watermelon 2 to 4 minutes or until grill marks form, turning once.
Carve steaks into slices. Cut each watermelon slice into 6 wedges. Season beef and watermelon with salt and pepper, as desired. Combine arugula and dressing in large bowl; toss to coat. Divide arugula among four serving plates. Arrange beef and watermelon on salad; top evenly with tomatoes, onion and cheese.
Nutrition information per serving: 285 Calories; 81 Calories from fat; 9g Total Fat (3 g Saturated Fat; 3 g Monounsaturated Fat;) 71 mg Cholesterol; 341 mg Sodium; 26 g Total Carbohydrate; 4.1 g Dietary Fiber; 29 g Protein; 3.9 mg Iron; 7.8 mg NE Niacin; 0.7 mg Vitamin B6; 1.4 mcg Vitamin B12; 4.7 mg Zinc; 29 mcg Selenium.
This recipe is an excellent source of Protein, Iron, Niacin, Vitamin B6, Vitamin B12, Zinc, and Selenium; and a good source of Dietary Fiber.