Preheat oven to 400 degrees F. Coat a large baking sheet with cooking spray.
For asparagus: Arrange asparagus on baking sheet and season with salt and black pepper. Wrap garlic cloves in foil and place on baking sheet next to asparagus. Roast for 15 minutes, until asparagus and garlic are golden brown. Remove from oven.
For tacos: While the asparagus is roasting, in a large skillet on medium-high heat, combine beef, chili sauce, green chiles, and chili powder and bring to a simmer for 5 minutes, or until liquid is absorbed.
For garlic-avocado cream: In a medium bowl, combine roasted garlic, sour cream and avocado. Mash with a fork until blended and smooth. Season, to taste, with salt and black pepper.
For the salsa: Chop 1/4 of the asparagus into small pieces, making about 1 cup, reserve remaining asparagus for soup, about 4 cups. In a medium bowl, combine chopped asparagus, diced tomato, cilantro, lime juice, and cumin. Season, to taste, with salt and freshly ground black pepper.
To serve, spoon beef into tortillas and top with shredded lettuce and cheese. Serve garlic-avocado cream and asparagus salsa on the side.