In a mixing bowl, combine the shrimp, olive oil, garlic powder, paprika, salt, and black pepper. Toss until the shrimp are well-coated.
Heat the skillet over medium heat. Add the seasoned shrimp and cook for about 3-4 minutes, turning occasionally, until the shrimp are pink and cooked through. Remove the shrimp from the skillet.
In the same skillet, place one tortilla. Sprinkle 1/2 cup of shredded cheese evenly over half of the tortilla.
Add 1/4 of the cooked shrimp, diced bell peppers, and cilantro (if using) on top of the cheese.
Fold the tortilla over to cover the filling and cook for about 2-3 minutes until the bottom is golden brown.
Carefully flip the quesadilla and cook the other side for another 2-3 minutes, until golden and the cheese is melted.
Repeat the process for the remaining tortillas and filling.
Once all quesadillas are cooked, slice them into wedges and serve with salsa and sour cream on the side.