Combine cilantro sprigs, ginger, garlic, andchiles in a resealable plastic freezer bag;seal. Lightly pound with a skillet or rollingpin until ginger and garlic are well mashed.
Add cucumbers, 1 teaspoon salt, and sugar.Seal bag; shake to mix. Squeeze bag firmlyto slightly mash cucumbers, 1-2 minutes.
Place bag in a large bowl; let macerate atroom temperature, turning halfway through,until juices form, about 35 minutes.
Empty contents of bag into bowl; turnbag inside out and scrape out any small bits.Discard cilantro sprigs.
Mix in celery, juice,and oil. Season with more salt, if desired.