Preheat a grill to medium. Peel the mangoes and cut the flesh from the pit in large flat slices; lay on a baking sheet. Season the mango slices with salt, black pepper and cayenne and drizzle with olive oil. Turn the slices over and repeat.
Grill the mango slices, turning once, until well marked, 2 to 3 minutes total. Transfer to a platter and squeeze the lime juice on top. Drizzle with the crema and top with jalapenos and cilantro.