Use a mandolin to slice potatoes thinly.
Toss slices in a big bowl with oil and salt to coat evenly.
Coat a large microwavable plate with cooking spray. Arrange some potato slices in a single layer on the plate.
Microwave, uncovered, on High until some slices start to brown, 2 to 3 minutes (depending on the power of your microwave).
Turn slices over (they will be hot, so take care with your fingers) and continue microwaving until they start to crisp and brown around the edges, for about 30 seconds.
Check frequently and rearrange slices as needed to prevent scorching.
Transfer chips to another plate and allow to cool completely. (They will crisp up more as they cool). Repeat process with remaining slices.
Storage: Store in an airtight container for up to 3 days.