Place asparagus in a medium bowl, add ice water to cover, and swirl asparagus with your hands. Drain through a fine-mesh sieve and return asparagus to bowl. Repeat process 2 more times (this will keep asparagus crunchy). Pat dry; wipe out bowl. Toss asparagus, scallions, lemon zest, garlic, cilantro, vinegar, and chile in dry bowl to combine. Add salt and sugar and toss again to combine.