Hold romaine heads at root end and cut into thin shreds. Peel onion and slice into thin rounds. Halve grape tomatoes. Stem cilantro. Rinse corn kernels under warm water if still frozen. Halve and juice lime.

Toss red onion in a medium mixing bowl with 2 Tbsp. lime juice and a pinch of salt. Marinate 10 minutes before serving, mixing a couple times to marinate evenly. While onions pickle, cook turkey.

Heat 1 tsp. olive oil in a large non-stick pan over medium-high heat. Add ground turkey and taco seasoning to hot pan. Cook until no pink remains, 6-8 minutes. Taste, and season with a pinch of salt and pepper if needed.

Halve avocados and, one at a time, remove pit by carefully tapping pit with the blade of your knife so it sticks. Gently twist knife to release pit. Scoop out flesh with a spoon. Cut avocado flesh into 1/2" dice.

Combine lettuce, grape tomatoes, avocado, and corn in a large mixing bowl. Toss with chipotle ranch dressing (to taste). Season with a pinch of salt and pepper, if desired.

Serve salad on a plate or in a bowl and top with turkey, pickled onion (to taste), cilantro, and a dollop of sour cream.