In a small mixing bowl combine peach preserves, dijon mustard, sriracha, and garlic; mix and stir until thoroughly incorporated.
Season pork tenderloin with salt and fresh ground pepper and coat with the peach mixture.
Place the pork tenderloin on a large sheet of aluminum foil, cut several slits across the top and insert peach slices in each slit. Set aside.
Cut the new potatoes in half, place in a bowl, season with salt and pepper, and toss with a tablespoon of olive oil.
Transfer potatoes to prepared foil, arranging them around the pork tenderloin.
Seal the foil packet well and place in the refrigerator for an hour or two.
Preheat your grill for 10-15 minutes with all the main burners on high.
Remove prepared foil packet from refrigerator and let stand at room temperature for about 15 minutes. DO NOT OPEN THE PACKET.
Place the foil packet over high heat on the grill; about 425°F.
Cook for 25-30 minutes, turning, until internal temperature of pork reaches at least 150°F.
Remove from grill and let stand a few minutes.
Open up the packet and serve. If you'd like, make additional glaze to serve over the pork tenderloin.