Place fish, 1 tbsp limejuice and black pepper in small bowl; stir well and let marinate at least 15 minutes, but not more than 30 minutes.
Meanwhile, combine tomatoes, onion and garlic in medium bowl.
Stir in serrano peppers; mix well.
Spray medium nonstick skillet with cooking spray; heat over "high" heat.
Add fish; cook and stir 2 to 3 minutes or until lightly browned.
Reduce heat to medium; cover and cook for about 5 minutes stirring occasionally, or until fish begins to flake.
Remove fish to clean bowl; set aside.
Return skillet to medium heat; add tomato mixture.
Cook and stir about 3 minutes or just until onions are soft.
Return fish to skillet; cook and stir 2 minutes.
Remove from heat.
Add remaining 2 tbsp limejuice and cilantro.
Serve over rice and garnish.
Ready in 35 min.