1) Coat a stove-top grill pan or griddle with cooking spray and set over medium-high heat to preheat. Season both sides of tuna with salt and cracked pepper. Place tuna on hot pan and cook 2 to 3 minutes per side for medium doneness.
2) Meanwhile, in a medium bowl, combine pineapple, papaya, onion, chilli pepper, lime juice, coriander, and chilli oil. Mix well and season, to taste, with salt. Serve tuna over noodles and spoon salsa over top.