Preheat your oven to 450 degrees Fahrenheit. Get out 2 large, well worn, seasoned baking sheets.
Scrub the potatoes and slice into 1/2" thick disks, lay the discs flat and cut into 1/2â€� batons or matchsticks. Put cut sweet potatoes in a large bowl -- big enough to toss them around.
In a smaller bowl, combine the egg white, oil and seasoning. Whisk with a fork or whisk until combined (and "not snotty" as my eloquent friend, Kristen, puts it) or get fancy and emulsify with a hand blender.
Pour the oil/egg white mixture over your sweet potatoes and toss to coat evenly.
Using your immaculately clean hands lift the coated sweet potato batons from the bowl (allowing any excess gunk to drip back into the bowl) and transfer to the baking sheet. Spread the fries out in a single layer so that none are touching -- this is a drag but critical to the crispiness factor of the finished fry. Bake both sheets in the oven and bake for about 15 min, at which time the fries will be half done.
Remove both trays from the oven and, using a metal spatula, loosen the fries from the baking sheet. Give the sheet a vigorous shake to make sure that all are free. Use a pair of tongs to turn each fry individually -- again, tedious but crucial to the crispiness factor.
Return the pans to the oven for another 10 - 15 minutes, until the fries are deep golden, brown and tender on the inside. You may have to sample a few just to be sure.
Once done remove fries from the oven, season cautiously with sea salt (they may already be quite salty from the Cajun seasoning) and serve right away. These babies do not like to sit around and you worked hard for all that crispiness!