1. In a medium bowl, whisk together lime juice, honey, salt, and pepper. Add diced peaches, red bell pepper, red onion, and cilantro. Toss gently to combine. Taste and adjust seasoning as needed. Set aside to let the flavors meld.
2. In a small bowl, mix brown sugar, salt, paprika, pepper, and garlic powder. Rub the pork all over with olive oil, then coat evenly with the seasoning blend.
3. Preheat the grill or grill pan to medium-high heat. Lightly oil the grates. Grill pork tenderloin, turning occasionally, until charred on all sides and internal temperature reaches 145°F—about 20 minutes. Optional: If the pork is very thick or not yet at temp, transfer it to a 400°F oven and roast an additional 10–15 minutes.
4. Let rest for at least 3 minutes before slicing.
5. Preheat the oven to 400°F. Heat 1–2 Tbsp oil in an oven-safe skillet over medium heat. Sear pork on all sides until browned, about 5–6 minutes. Transfer skillet to oven and roast 15 minutes more, flipping halfway through. Internal temp should read 145°F. Rest 3 minutes before slicing
6. Slice pork and arrange on a platter. Spoon peach salsa generously over the top. Garnish with fresh herbs, if desired. Serve immediately.