SARATOGA SPRINGS — For Hall of Fame trainer Steve Asmussen, explaining Echo Zulu’s dominance is fairly cut-and-dry. “It’s as simple as she’s faster than other horses,” Asmussen said. Echo Zulu proved that emphatically on Saturday at Saratoga Race Course, setting the pace in the Grade I, $500,000 Ballerina just in front of defending champion Goodnight Olive before drawing away impressively under jockey Florent Geroux for a 2 1/2-length victory. Echo Zulu completed the 7-furlong sprint in one minute, 20.95 seconds. “Felt like I was in control pretty much all the way through the race,” Geroux said, “and when I asked…