枚

1. counter counter for thin, flat objects (e.g. sheets of paper, plates, coins)
2. counter for portions of gyōza or soba
3. sumo counter for ranks
4. sumo counter for wrestlers of a particular rank
5. counter for fields or rice paddies
6. counter for palanquin bearers

ひら also 片

1. counter counter for thin, flat things (petals, leaves, etc.)

びら

1. noun, usually in kana bill; handbill; flyer; flier; leaflet; poster; placard