Puree mangos in a blender. Add rice wine vinegar and chili garlic paste and blend until all ingredients are incorporated (the color should be a bright orange-red). Bring marinade to a boil. Lower heat to medium-low and reduce to about half (about 10 minutes over medium-low heat).† The sauce can be strained at this point to remove the bits of garlic and ginger (the flavor is slightly less intense but it makes for a nicer presentation). Add about half of the mango puree (approximately 2/3 cup) and cook for another 2 minutes. Set aside.
Save the other half of the mango puree for garnish.