Preparation Place first 5 ingredients in heavy large saucepan. Add enough water just to cover ham hocks. Season with pepper. Reduce heat and simmer until ham is very tender, turning occasionally, about 3 hours. Remove ham from bone and shred. Discard bones and fat. Transfer 4 cups ham to large bowl (reserve any remainder for another use). Combine sour cream, mayonnaise, chopped cilantro and cumin in medium bowl. Add celery, carrots, green onions, chilies and 3/4 cup sour cream dressing to ham and stir to combine. Season with salt and pepper. (Can be made 1 day ahead. Cover ham mixture and remaining dressing separately and chill.) Place 2 large lettuce leaves on each plate. Thinly slice remaining lettuce. Sprinkle sliced lettuce atop whole leaves in center of plate. Mound ham filling in avocado halves. Place atop bed of lettuce. Spoon enough remaining dressing over to cover filling completely. Garnish with cilantro sprigs and lime.
Preparation Place first 5 ingredients in heavy large saucepan. Add enough water just to cover ham hocks. Season with pepper. Reduce heat and simmer until ham is very tender, turning occasionally, about 3 hours. Remove ham from bone and shred. Discard bones and fat. Transfer 4 cups ham to large bowl (reserve any remainder for another use). Combine sour cream, mayonnaise, chopped cilantro and cumin in medium bowl. Add celery, carrots, green onions, chilies and 3/4 cup sour cream dressing to ham and stir to combine. Season with salt and pepper. (Can be made 1 day ahead. Cover ham mixture and remaining dressing separately and chill.) Place 2 large lettuce leaves on each plate. Thinly slice remaining lettuce. Sprinkle sliced lettuce atop whole leaves in center of plate. Mound ham filling in avocado halves. Place atop bed of lettuce. Spoon enough remaining dressing over to cover filling completely. Garnish with cilantro sprigs and lime.