We've featured this shrimp fajita salad in the past (most recently in 2017) and it always gets great reviews from our community for coming together quickly and offering great color and texture.
Make dressing - Chop garlic. Whisk garlic with vinegar, mustard, honey, paprika (portion for dressing), and cooking oil (portion for dressing). Season to taste with some salt and pepper. (Can be done up to 5 days ahead)
Shrimp - Defrost, rinse, and pat dry. Toss with garlic powder, paprika (portion for salad), coriander, cumin, and some salt. (Can be done 1 day ahead)
Shallots / Bell Peppers / Green onions - Prep as directed. Store separately. (Can be done up to 3 days ahead)
Heat a nonstick pan or skillet over medium-high heat. Add cooking oil (portion for salad) and then shallots to heated oil with a pinch of salt. Saute until softened, ~3 minutes.
Add peppers and saute for 3 minutes more.
Fold in shrimp and toss until shrimp are cooked through, 4 to 5 minutes.
Assemble salads with lettuce and avocados. Toss with shrimp, peppers, and dressing. Season to taste with some salt and pepper. Sprinkle green onions and pepitas on top.