How can I use up a LOT of pico de gallo, "fresh" salsa left over from a catering event?

You can also put it in a jar, that last for about a week or so.

Could you cook it down in some oil to make a sofrito that you could use as a base for future recipes? You can freeze sofrito in small quantities and add a bit to rice, chicken, beans, stews, etc.

Other ingredients would be chicken stock,cumin, chili powder, crushed tortilla chips, a bit of coriander and some corn.

Make tortilla soup. Put the pico de gallo in the pan. Saute it- then puree. Proceed with the other ingredients.

Make soup by adding chicken broth and freeze it in containers. When ready to use, add shredded chicken and taco chips. Top with shredded cheddar a dollup of sour cream....Taco Soup! BB

Bottle it prettily, pack with a few related foods, and use as a promotional or thank you gift.

It can work pretty well as an ingredient in mixed rice (or other grain) and mixed vegetable (combines especially well with corn) dishes, but "cups and cups" might be a bit difficult. Also can be mixed with simple ingredients such as cooked seafoods for a taco filling. Should freeze decently.