Heat the oven to 400°F. Drain and rinse the chickpeas, then spread them on a clean kitchen towel and pat them very dry — any moisture left on the skins keeps them from crisping.
In a large bowl, toss the dry chickpeas with the olive oil, smoked paprika, garlic powder, salt, black pepper and cayenne (if using) until evenly coated.
Spread the chickpeas in a single layer on a large rimmed baking sheet. Discard loose skins and make sure no chickpeas are stacked on each other.
Roast for 25 to 30 minutes, shaking the pan at the halfway point, until the chickpeas are golden brown and crisp. Some may pop in the oven — that is normal.
Taste one: if the center is still soft, roast 3 to 5 more minutes. They firm up and get crunchier as they cool.
Cool on the pan for 5 minutes, then serve. Store leftovers loosely covered at room temperature for up to 3 days — an airtight container traps steam and makes them soft.
