Dice the mango, onion, and tomato and place in bowl. Finely mince the garlic and cilantro, then add to the bowl.
Add lime juice, sea salt, and black pepper to taste. Stir to combine, and re-season if needed.
Toss the shrimp with salt, pepper, and two tablespoons of olive oil. Sauté, place in large skillet over medium-high heat, or skewer and grill. Cook for about 4 minutes per side, or until thoroughly cooked and pink.
Slice the avocado and place two or three slices in each leaf of lettuce to serve as the taco shell. Top with the Mango Pico de Gallo and the warm shrimp, then drizzle with lime juice and dive in!