Top 4 tortillas evenly with kimchi, then with cheese, avocados, and remaining tortillas.
Mix oil, vinegar, and sesame seeds in a small bowl; set aside.
Heat a 12-in. frying pan over medium-high heat. Toast each quesadilla until lightly browned and cheese has melted, 1 to 2 minutes per side. Slice each quesadilla into wedges, sprinkle with cilantro, and serve with sesame dipping sauce.
Note: Nutritional analysis is per serving.