Preheat the oven to 350°F.
Brown the pork tenderloin well in a drizzle of oil in a skillet set over medium-high heat.
Pop the skillet in the oven and roast for 15-20 minutes, or until just cooked through.
Remove the pork from the pan and tent with foil on a cutting board.
Add another drizzle of oil to the pan (don’t wash it out) and cook the onion and garlic for 4-5 minutes, until soft.
Add the tomatoes, salsa, peanut butter, chipotle, chili powder, cumin and salt and bring to a simmer, stirring to loosen any browned bits in the bottom of the pan.
Simmer for 10-15 minutes. Slice the pork and stir it into the pot; serve over rice, topped with peanuts.