Preheat oven to 350°F.
Wash and dry the potatoes. Poke several holes; I like to use a meat fork about 6 times per potato. Coat the potatoes with olive oil, then sprinkle with kosher salt.
I prefer to use a small wire rack placed on a half sheet pan; this makes it easier to get the potatoes in and out of the oven, especially if you're sharing the oven with something else that you are cooking.
It should take about an hour to cook the potatoes at 350°F; it may take as long as 1:15.
I've seen cooking temperatures as low as 300°F for 1:30 to 1:45, so there is some flexibility if you want to cook something else with your potato.