In a blender or food processor blend the avocado, tomatillos, cilantro, water and salt, until you get a smooth puree. Set aside. In a blender or food processor blend the tomatoes, chipotles, water and salt, until you get a smooth puree. Set aside.
Season the shrimp with salt and on a grill or broiler cook the shrimp until tender; (being careful not to overcook).
On a medium-size plate place the avocado sauce on half of the plate, and on the other half the tomato-chipotle sauce; garnish the plate with the mango slices and set the grilled shrimp between the 2 salsas.