Set a large skillet over high heat. When the skillet is hot, add the oil.
Add the diced bell pepper and jalapeno. Cook 3-4 minutes, until beginning to soften.
Add the corn kernels, scallion, and seasoning. Cook for 2-3 minutes, until warmed through. Stir in the cilantro and set aside.
Heat a second pan over medium-high heat. Add as many tortillas as will fit in one layer. Sprinkle the tortillas with shredded cheese, if using, and fold them in half like a quesadilla. Cook 1-2 minutes per side, until the tortilla is warmed through and the cheese is melted. Repeat with the remaining tortillas. Keep warm.
In the same pan you used for the tortillas, heat the shrimp, covered, until warmed through, about 3 minutes. Stir the shrimp into the corn mixture.
To serve, open each tortilla. Spoon the shrimp and corn filling over the melted cheese. Top with cotija cheese.