Preheat the oven to 400 degrees F. Line several baking sheets with parchment paper and set aside. Use a mandolin slicer to cut the sweet potatoes into paper-thin rounds. (I set mine to the thinnest setting.) You can use a knife to do this, but it takes much longer.
Pile all the sweet potato rounds into a large bowl and pour the olive oil over the top.
Gently toss to coat every piece with oil. Then lay the sweet potato rounds out on the baking sheets in a single layer.
Sprinkle the chips lightly with sea salt. Bake for 20-25 minutes until crisp and golden around the edges. Remove from the oven and cool for 5 minutes on the baking sheets. Then move the chips to a bowl, or plastic bag to store.
If you happen to find a few chips with soft centers, pop them back in the oven for about 5 minutes.