Place chiles and water in a skillet and simmer until soft, about 2 minutes. Add sesame oil and garlic; cook until fragrant, 1 to 2 minutes. Stir in blueberries, apple cider vinegar, sugar and salt. Bring to a boil and cook, mashing berries with a wooden spoon until a thick sauce forms, 5 minutes. Remove from heat. Divide sauce over salmon fillets.