Heat oil in a medium skillet, add beef and cook until just starting to brown, breaking up larger pieces as it cooks. Drain or dab out any excess fat.
Add green pepper, onion and garlic. Continue to cook for 2-3 minutes until vegetables start to soften and beef is fully browned and cooked through.
Stir in water, taco season, and red pepper flakes. Cook over medium until liquid has evaporated, about 8 minutes.
Stir in black beans and corn and heat until warm. Adjust salt to taste.
Heat a large skillet over medium heat and drizzle in 1/2 tsp of oil. Add one tortilla and sprinkle the entire tortilla with 1/2 cup of grated cheddar cheese (about 2 ounces). Spread approximately 1 cup of beef mixture evenly over half of the cheese-covered tortilla.
Allow to cook until the bottom of the tortilla is golden and the cheese is melted. Fold the tortilla in half and press gently to hold it together. Remove to a cutting board and cut into 3 wedges. Repeat with remaining tortillas and serve immediately with your favourite garnishes like sour cream and salsa.