Heat the oven to 400 degrees. In a large bowl, stir together the lime juice, brown sugar, fish sauce and chile until the sugar dissolves. Coat the tenderloin with 1 tablespoon of the sauce, rubbing to coat. Set the rest aside.
In a large cast-iron skillet over medium-high, heat 1 tablespoon oil. Add the pork and cook until browned all over, 6 to 8 minutes. Turn off the heat, then add the remaining tablespoon oil and the corn. Stir to coat. Transfer the skillet to the oven and roast until the corn is tender and a thermometer inserted into the thickest part of the pork registers 140 degrees, 10 to 14 minutes. (The pork will continue to cook as it rests.)
Meanwhile, thinly slice the peaches, cucumbers and red onion.
Transfer the pork to a cutting board to rest for at least 5 minutes, then thinly slice and season the cut sides lightly with salt. Transfer the corn, peaches, cucumbers and red onion to the bowl of sauce. Stir to combine and season to taste with salt. Serve the pork topped with salad and all of the sauce.
Tip:To remove the silver skin, a tough connective tissue, without cutting off too much meat, locate the white, shiny membrane and insert your knife at one edge of the silver skin to cut between the skin and the meat, creating a flap to hold onto. Pulling the flap of silver skin tight with your non-dominant hand, continue to slice along the length of the skin until you’ve removed and released all the silver skin.