The essay is where the admissions reader is trying to get to know you as a person. What drives you as a person? How can you make yourself stand out to the college? Cultural background, something else? Essay cannot be race alone but if race/ethnicity has a big impact on your life to date it can be discussed.
The key is to show, not tell. And the easiest way is from a first-person perspective of a key part of your personality. Check out some webinars or videos of college essays. Or other successful essays.