Prep the dressing. In a small bowl, whisk olive oil, lime juice, lime zest, garlic, Dijon, salt, pepper, and smoked paprika or chili powder.
Taste and adjust salt or lime as needed. Set aside.
Season the shrimp. Pat shrimp dry with paper towels. Toss with olive oil or ghee, a pinch of salt and pepper, and garlic powder if using.
Cook the shrimp. Heat a skillet over medium-high.
Once hot, add shrimp in a single layer. Cook 1.5–2 minutes per side until pink and opaque. Do not overcook.
Transfer to a plate to cool slightly.
Prep the vegetables. Dice avocado and cucumber, halve tomatoes, thinly slice red onion, and chop cilantro or parsley. If using greens, add them to a large bowl first.
Assemble the salad. Add cucumber, tomatoes, onion, and herbs to the bowl. Drizzle in half the dressing and toss gently.
Fold in the shrimp and avocado last to avoid smashing the avocado.
Finish and serve. Add more dressing to taste. Season with a final pinch of salt and pepper. Serve right away while the shrimp is still slightly warm for the best texture and flavor.