In a medium bowl, toss the shrimp with olive oil, garlic powder, paprika, salt, and pepper until well coated.
Heat a large skillet over medium heat. Add the seasoned shrimp and cook for 2-3 minutes on each side, or until they are pink and cooked through. Remove from heat and set aside.
In the same skillet, reduce the heat to low. Place one tortilla in the skillet and sprinkle half of the Monterey Jack and cheddar cheese evenly over it.
Add half of the cooked shrimp and half of the diced bell peppers on top of the cheese. Sprinkle with half of the cilantro if using.
Top with another tortilla and cook for about 2-3 minutes, or until the bottom tortilla is golden brown and the cheese is melted.
Carefully flip the quesadilla using a large spatula and cook for an additional 2-3 minutes on the other side until golden brown and crispy.
Remove from the skillet and let it cool for a minute before slicing into wedges. Repeat the process with the remaining ingredients to make a second quesadilla.
Serve warm with sour cream and salsa on the side.