- HEAT grill to medium heat.
- COOK onions in boiling water 5 min. or until tender; drain. Place onions in medium bowl. Add vinegar and sugar; mix well. Refrigerate until ready to use.
- GRILL chicken 5 to 6 min. on each side or until done, brushing with barbecue sauce for the last 5 min. Cut into thin strips.
- TOP tortillas with chicken, onions and Singles; fold in half. Grill 1 to 2 min. on each side or until Singles are melted and quesadillas are lightly browned on both sides. Sprinkle with cilantro.
- Substitute: Substitute 2 sliced green onions for the cilantro.