A Gramillian sand pea was a seed that could be eaten.
Pel suggested to Quark that he serve Gramilian sand peas in his bar on Deep Space 9. The sand peas would make the person eating them thirsty and more likely to purchase more drinks. (DS9 episode: "Rules of Acquisition")
Miles O'Brien once demonstrated a trick to Julian Bashir where he placed a Gramilian sand pea on his hand, before launching the sand pea into his mouth. O'Brien liked sand peas with Yamok sauce. (DS9 episode: "The Way of the Warrior")