Spoon lasagna filling into a large skillet and add chili powder and cumin. Bring mixture to a simmer over medium heat. Simmer 5 minutes. Meanwhile, in a medium bowl, combine mango, jalapeno, red onion, cilantro, and lime juice. Season, to taste, with salt and black pepper. Serve beef mixture with taco shells, lettuce, grated cheese, sour cream, and mango salsa on the side.