Chicken Quesadillas

Name: Chicken Quesadillas
Ingredients: 1 lb. skinless, boneless chicken breasts, preferably thin sliced; 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt; 2 tsp. paprika; 1 tsp. ground coriander; 1 tsp. ground cumin; 1 tsp. sugar; 3–5 Tbsp. vegetable oil, divided; 1 small onion, cut into ½ pieces; 1 small red bell pepper, ribs and seeds removed, cut into ½ pieces; 2 garlic cloves, finely chopped; 1 jalapeño, thinly sliced; 12 oz. pepper jack cheese, coarsely grated (2–3 cups); ½ cup (packed) coarsely chopped cilantro; 6 8–10-diameter flour tortillas