Drain all canned goods and mix together in a large non metal bowl. Chop onion and mix in. Add cilantro to taste.
A squirt of lime juice makes for a tasty addition, but should only be used if the salsa is going to be used immediately, otherwise the juice seems to hasten the "aging" process. Without the lime juice this can be refrigerated for several days, but it usually never lasts more than 1-2 days!
I like to serve it with blue corn chips and Fritos for a colorful side dish or appetizer.