Add dried hibiscus flowers, torn ancho chiles, and dried apricots to a small saucepan with 1/2 cup water. Bring to a simmer over medium heat and cook 8 to 10 minutes until softened and liquid is deep red.

Transfer all solids and the simmering liquid to a blender. Add tamarind paste, sugar, lime juice, white vinegar, and 1/2 teaspoon tajín.

Secure the blender lid tightly and blend on high for 45 to 60 seconds until completely smooth.

Pour the blended sauce through a fine mesh strainer into a bowl or jar, pressing with a spatula to extract all the sauce. Taste and adjust with more lime, sugar, or tajín as needed.

Peel and slice mangoes into thick half-inch slabs or long spears. Arrange in a bowl.

Drizzle chamoy sauce generously over the mango slices. Squeeze fresh lime juice over top. Dust with tajín to taste and serve immediately.