Guang Cui and Daniel Sun are members of the class of 2022, course 6.3 (Computer Science and Engineering) majors, former roommates, best friends — and now, alumni of the long-running TV competition “American Ninja Warrior.” The episode in which they debuted (season 13, night 4 of qualifiers) as first-time competitors recently aired on NBC, and is available on several streaming services. They spoke recently about what it takes to be a ninja. Q: How did you decide to try for this goal — were you both already fans of “American…
