In a bowl or zip-top bag, mix the orange juice/zest, lime juice/zest, olive oil, garlic, Dijon mustard, thyme, salt, and black pepper.
Add the pork tenderloin and marinate in the fridge for 30 minutes to 4 hours.
Next, make the salsa. Combine all of the ingredients in a bowl. Toss gently and refrigerate until ready to serve.
If you're grilling the pork, you want to preheat the grill (or grill pan) to medium-high heat.
Remove pork from marinade, pat dry slightly, and spray lightly with cooking oil.
Grill for 12-15 minutes, turning occasionally, until internal temperature reaches 145 degrees F.
Let the pork rest 5 minutes before slicing.
If you don't have a grill, the pork can also be roasted in the oven. Preheat the oven to 425 degrees F and roast for 20-25 minutes.