Heat oil in a large nonstick skillet over medium-high heat. Add onion and pepper; cook 3 minutes, stirring occasionally. Add shrimp; cook an additional 3 minutes, until shrimp is opaque. Stir in corn, 1/4 cup water, chili powder and cumin. Heat through.
Heat oven to 375 degrees F. Coat a 13 x 9 x 2-inch baking dish with nonstick cooking spray.
Wrap four tortillas in damp paper towels. Microwave 30 seconds. Brush one side of each tortilla with salsa. Spoon 1/2 cup shrimp mixture on each. Roll up and place seam-side down in prepared dish. Repeat with remaining tortillas and filling. Top with any extra filling.
Mix remaining salsa with half-and-half. Spoon over enchiladas. Sprinkle with cheese. Bake at 375 degrees F, uncovered, for 15 minutes or until bubbly.