Answer:
There are millions of me. I am very small but when moving fast I am deadly.
What has 13 hearts but none beat?
What stays on the ground but never gets dirty?
In the evening I'm long, in the morning I'm smallΝΎ When seen in a ballroom, I'm nothing at all.
When set loose I fly away. Never so cursed as when I go astray.
This food is a tortilla filled with cheese and sometimes chicken before being heated or cooked.