Stir the rice and 1/2 cup water together in a microwave-safe bowl. Cover, and cook in the microwave on High for 6 minutes until the water is fully absorbed; set aside. While the rice is cooking, heat a large skillet over medium-high heat and stir in the ground beef. Cook and stir until the beef is crumbly, evenly browned, and no longer pink. Drain and discard any excess grease.
Reduce heat to medium, and stir in the taco seasoning, corn, 1/2 cup water, 1 1/2 cups Cheddar cheese, and the cooked rice. Cook and stir until the cheese has melted and the corn is hot. Spoon the mixture into the flour tortillas. Roll into a tight cylinder, and pack into an 8x11-inch baking dish (it will be a tight squeeze). Pour the salsa over top, and sprinkle evenly with 1 1/2 cups Cheddar cheese.
Bake in the preheated oven until the cheese topping has melted and is beginning to brown, about 10 minutes.