1. Combine first 6 ingredients in a medium bowl, stirring with a whisk.
2. Heat an 8-inch nonstick skillet over medium-high heat; coat pan with cooking spray. Add egg mixture, and cook until edges begin to set. Gently lift edges of egg mixture with a wide spatula, tilting pan to allow uncooked egg mixture to come in contact with pan. Cook 2 minutes or until egg mixture is almost set; sprinkle with cheese. Spoon tomato over half of omelet; fold in half.
3. Cut omelet in half crosswise, and slide one half onto each of 2 plates. Garnish with cilantro, if desired, and serve immediately.
Serve with: Mandarin Oranges with Kiwifruit and Grapes