Murasakis are also known as Japanese sweet potatoes (even though they were actually developed in Louisiana). They are known - and loved - for their dark red skin and starchy, pale white interior. Their higher starch content means they char and caramelize where an orange sweet potato might collapse and get soggy. This makes them ideal for sweet potato fries, roasting, or just baking to enjoy their champagne-colored flesh.
Store in a cool, dark place.
I definitely recommend refrigerating these skinny tubers. They were very sweet when tossed with oil and salt and roasted for about 25 min at 400F. (I stirred them every 10 minutes and after 20 minutes kept checking to see if they could be pierced with a fork). I also tried sliced thinly and pan fried and oven roasted was vastly superior.