For maximum flavor, refrigerate steaks for 2 hours after rubbing with spice mixture. Tomato Relish can also be prepared earlier in the day and refrigerated until ready to serve.
Mix sugar, cumin, oregano, sea salt, garlic powder and cayenne pepper in small bowl until well blended. Reserve 1 tablespoon of the spice mixture. Brush steaks lightly with oil. Rub remaining spice mixture on both sides of steaks. Refrigerate 30 minutes or longer for extra flavor
Meanwhile, mix tomatoes, onion, oil, vinegar and reserved spice mixture in medium bowl. Cover. Refrigerate until ready to serve
Grill steaks over medium-high heat 6 to 8 minutes per side or until desired doneness. Slice steak and serve with Tomato Relish