A cigarette lighter like this one usually has its cover opened by a flick of the thumb.
[transitive verb] to make something move quickly and suddenly, especially with a quick movement of the hand. He flicked a speck of cigarette ash off his sleeve.
flick something over/across/at/into/back/down etc.: She flicked back her long dark hair.
flick something open: He flicked open the file in front of him.
Does the Portuguese estalar work for you?
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