Place the sweet potato sticks in a bowl and add enough cold water to cover them.
Sprinkle in two teaspoons of salt and allow the sticks to soak for at least 30 minutes (longer if possible).
Preheat the oven to 450 with a baking sheet inside.
When the sweet potatoes are done soaking, drain them and place on a paper towel to dry.
Add the corn starch, one teaspoon salt, the paprika, garlic powder, black pepper, and cumin to a gallon sized ziploc bag.
Add the sweet potato sticks to the bag and shake to coat.
Add the vegetable oil to the bag and shake again to coat.
Remove the hot baking sheet from the oven and place a piece of parchment paper on top.
Pour the sweet potato sticks over the top and spread them apart as much as possible.
Return the baking sheet to the oven and bake the fries for 20 minutes.
Flip the fries and continue to bake for another 10-15 minutes, or until crisp.
Remove from the oven and serve hot, sprinkling with additional salt if desired.