Heat 2 tablespoons oil in a large skillet over medium-high heat. Add onion and bell peppers; cook, stirring frequently, until onion is translucent and peppers are soft, 6 to 8 minutes. Add salt, cumin, and chili powder; stir to coat vegetables.
Add shrimp; cook and stir until shrimp are opaque and no longer pink in the center, 3 to 5 minutes. Remove from the heat and stir in minced jalapeño and lime juice.
Heat another skillet over medium heat and brush with about 1 teaspoon oil. Place one tortilla in the hot skillet; spoon about 1/6 of the shrimp filling and 1/2 cup Mexican cheese blend onto one side of tortilla. Fold tortilla in half. Cook until lightly browned on the bottom, about 5 minutes. Flip and cook until lightly browned on the other side, 3 to 5 minutes. Repeat to make remaining quesadillas.
