Drop the garlic through the feed tube of a food processor with the metal blade in place and motor running to chop finely (about 10 seconds.) Add the scallions, parsley, cilantro, and jalapeno and chop finely (about 6 pulses of the motor). Add the tomatillos and process until pureed, about 5 seconds. Add the remaining ingredients and pulse 2 times to mix. Refrigerate, covered.