In a large mixing bowl combine shrimp, garlic, lime juice, thyme, salt and white pepper; mix well.
Lightly oil large skillet with cooking spray and cook shrimp on medium high for 5-6 minutes, stirring occasionally. Remove shrimp from skillet; set aside.
In same skillet add corn, bell peppers and onions; cook on medium until corn is tender.
Add shrimp and tomatoes to skillet and cook until shrimp are opaque in the center.