Combine the chicken, cilantro, BBQ sauce and red onion, set aside.
Preheat your oven to 350 degrees. Line a large baking sheet with a silicone baking mat.
Place the mozzarella slices on the silicone baking sheet. Bake 5-7 minutes.
When the edges have browned and the cheese is bubbly (watch the video if you need some guidance) remove from the oven. Allow them to cool about 1 minute, just so they cool enough you can handle, but still very pliable.
Place the chicken mixture on the edge of one slice and tightly roll them up, seam side down.