Cook rice in water as directed on package.
Meanwhile, melt butter in large skillet over medium heat. Add shrimp, garlic, salt and pepper; cook 5 minutes or until shrimp turn pink, stirring occasionally.
Add salsa, clam juice and chiles; mix well. Reduce heat to low; cook 5 minutes.
In small bowl, combine water and flour; blend until smooth. Add to mixture in skillet; cook 2 minutes or until slightly thickened, stirring constantly. Serve in bowls, with or without rice.