someone who picks beans with his or her hands or using a knife (see Molina)
Alonso de Molina:
etequini. cogedor de frisoles desta manera. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 29r. col. 1. Thanks to Joe Campbell for providing the transcription.