Defrost shrimp in a bowl with water.
Chop and wash romaine lettuce. While romaine lettuce is soaking in warm water (This makes them come back to life) and the shrimp is defrosting, get started on prepping the other ingredients.
Mince one large garlic clove for the shrimp.
Dice tomatoes. I like to peel and deseed my tomatoes but this is not a necessary step.
Get your frying pan hot, add a drizzle of olive oil (about 1 tbsp) and add the minced garlic to the pan. Add the shrimp and let cook on one side until done. About 1 minute. You can add a splash of white wine or a small pad of butter to allow shrimp to steam a little. Turn and cook the other side for about a minute. Add salt and pepper to taste.
Assemble the salad in a 8 cup Tupperware. Save some room for your avocado that you'll add just before eating. Add 4 cups of lettuce, top with half the tomatoes and half the shrimp. Wait until your shrimp is completely cooled.
When you're ready to eat, add half of the avocado and tightly wrap up the other half to use the next day. Add some onion salt, the olive oil and apple cider vinegar.