Place the almonds, olive oil, thyme and kosher salt on a sheet pan and toss them together. Roast the almonds for 10 to 15 minutes, turning them every 5 minutes with a metal spatula, until they're lightly browned. Watch them carefully; they go from underbaked to burnt very quickly.
Sprinkle with fleur de sel, toss and set aside to cool. Serve warm or at room temperature. (Store the cooled nuts in a sealed container at room temperature for a week or two.)