1
For the glaze: In a food processor, pulse the peaches, jalapeños, onion, and ginger until shredded and juicy, but not fully puréed. Transfer mixture to a large Dutch oven and add the vinegar, sugar, and salt. Bring up to a boil and skim any foam that finds its way to the top (this makes for a clearer glaze). Cook the sauce over a medium simmer for 30 minutes. Test for viscosity. It should be thicker than cream and pool up like honey.
2
For the chicken: Pre-heat oven to 400°F. On a parchment-lined sheet pan, season chicken with salt and pepper. Roast for 15 minutes in an even layer. Remove from oven and slather chicken thighs with the glaze. Return to oven and continue to roast another 15-20 minutes or until chicken reaches 165°F and is slightly caramelized.