What appetizers are best for a margarita party?

I'd think anything Mexican. Tacos are almost like appetizers and people love them because they can make their own. If you wanted something smaller, you could serve strips of Mexican pizza. You can get good plain cheese ones that are frozen and add spiced beef, Monterey Jack and cheddar cheese, onions, jalapenos and black olives. Also, gaucamole dip with tostitos - the lime ones are really good.