Step 1Puree tomatillos with liquid, garlic, green onion and salt in food processor or blender. Mix with sour cream in bowl until blended. Makes 2 cups.
Step 1Cut corn kernels from cob into large bowl. Stir in black beans, celery, tomato, red onion, cilantro, pepper, salt and lime juice.
Step 2To serve, spoon mixed vegetables into warm corn tortillas and top with tomatillo-sour cream dressing.