Rinse sage leaves and lay flat on a double layer of paper towels; cover with more towels and press gently to flatten and dry leaves. Pour oil into a narrow 1- to 1 1/2-quart pan over medium-high heat to a depth of 1/4 inch. When hot (oil will ripple), lower heat to medium and add sage leaves, a few at a time, in a single layer. Fry just until oil stops bubbling around leaves, 10 to 15 seconds (do not let brown), then remove carefully with tongs and drain on more paper towels. Sprinkle with salt to taste. Use at once, or store between layers of paper towels in an airtight container at room temperature for up to 1 day.