Preheat grill or grill pan to medium-high heat.
Combine the mango, tomatoes, jalapeno, cilantro and lime juice in a medium mixing bowl and season with salt and pepper. Season the fish with salt and pepper and brush with olive oil. Grill for roughly 3 to 4 minutes per side, until just opaque in the center. Set aside to cool
When slightly cool, chop into large chunks. Add to the reserved salsa and fold carefully as to not break up the fish. Add mixture to the middle of the lettuce leaves and roll.