Method:

1. Season pork generously with salt. Set, skin side up, on a wire rack set inside a rimmed baking sheet. Chill at least 12 hours and up to 2 days.

2. Preheat oven to 175 °C. Pour 4 cups water into baking sheet with pork. Rub pork skin with oil, season with more salt. Roast, adding more water to pan as needed, until skin is golden brown and an instant-read thermometer inserted into thickest part of pork registers 90°C, 1 1/2–1 3/4 hours.

3. Meanwhile, pour out 1/2 cup vinegar from bottle (save for another use). Remove pouring spout from bottle and add garlic, chiles, and a large pinch of salt. Cover and shake to distribute, let sit until ready to serve. 

4. Bring hard cider and honey to a boil in a large saucepan; cook until thickened and very syrupy, 30–45 minutes.

5. Increase oven temperature to 230°C. Continue to roast pork until skin is browned and puffed, 15–20 minutes (add a few more splashes of water to baking sheet if juices are scorching). Transfer rack with pork to a cutting board; let rest 20 minutes.

6. Pour off fat from baking sheet and add 1/2 cup water, scraping up browned bits. Return baking sheet to oven for a few minutes if needed to help loosen browned bits. Stir into reduced cider mixture.

7. Remove skin from pork, using the tip of a knife to get it started (it should come off in 1 large piece with a little help). Slice pork lengthwise into 2"-wide strips, then crosswise into 1/2"-thick pieces. Transfer to a platter and drizzle with reduced cider mixture. Break skin into large pieces and arrange on top, place a few chiles from vinegar around. Serve with chile vinegar.