Joanna's Ceviche

Modified from the cookbook "Cooking With Two Hot Tamales" by Mary Sue Millikenand Susan Feniger
This is about double what the original recipe calls for -- but I always make double.
2 pounds cooked and peeled shrimp (I usually buy bags of frozen cooked peeled shrimp -- but you can use raw shrimp and just boil it in salted water for a couple of minutes)
1 cup feshly squeezed lime juice
2 tsps coarse salt
1/2 tsp black pepper
2 small avocados, seeded, peeled and diced
2 minced garlic cloves
12 tomatillos, husked, washed and diced (although I have been substituting one small can tomatillo salsa verde for half the tomatillos, or two small cans for all of them)
4 jalapenos, stemmed, seeded and chopped
2 bunches thinly sliced scallions
2 bunches cilantro, leaves only, chopped
Put cooked shrimp, lime juice, salt and pepper in a glass or ceramic bowl. Marinate in the refrigerator for 1 hour.
Drain the shrimp, but keep the lime juice.
In a glass or ceramic bowl, combine shrimp and all other ingerdients. Add lime juice to taste.