Line a rimmed baking sheet with paper towels.
Spread beans in an even layer on paper towel-lined pan; thoroughly pat dry, and let air-dry for 30 minutes.
Preheat oven to 350°. Line a rimmed baking sheet with parchment paper.
Place beans on parchment-lined pan; toss with oil and salt.
Bake until crispy, 40 to 45 minutes, stirring halfway through baking. (Beans will burst open when baking.)
In a small bowl, stir together chopped thyme, garlic powder, paprika, onion powder, oregano, black pepper, and cayenne; immediately sprinkle thyme mixture onto hot beans, stirring until well coated. Garnish with thyme leaves, if desired. Serve immediately. Beans are best eaten the same day but will keep in an airtight container for up to 3 days.