1. Combine jalapeno and celery in a large bowl; set aside. In a small bowl, combine orange juice, sherry, and honey; season with salt and pepper. Pour orange mixture over jalapeno-celery mixture. Add orange zest; toss to combine. Set aside.

2. In a medium bowl, combine pears, apples, ginger, sugar, and lemon juice; set aside. Spray a grill pan with cooking spray. Heat over medium-high heat until hot but not smoking. Grill onion rounds, basting with a little liquid from pear-apple mixture. Cook each side until softened and slightly charred, 3 to 5 minutes per side. Transfer onions to a cutting board; cut into 1/4-inch cubes. Add to jalapeno-celery mixture.

3. Grill apple and pear quarters in batches, until golden brown on each side, basting with collected juices in bowl, 2 to 5 minutes per side. Transfer to a cutting board; cut into 3/4-inch cubes. Add to jalapeno-celery mixture along with juices. Chop celery leaves; add to jalapeno-celery mixture along with lemon zest. Stir to combine. Let sit at least 1 hour at room temperature. Season to taste.