Fry in a pan with vegan margarine. As they cook, brush tops with hot sauce. Flip, repeat.
Serve with generous heaping sprinkles of brown sugar, and if you have it, vegan sour cream.
A veggie restaurant near me serves what they call "Orleans Fries" - slice the yams lengthwise into 1/4 inch / 6 mm thick "chips", then lengthwise again to make 1/2 inch / 13 mm or so thick "fries".