Season shrimp with chili powder. Set a nonstick skillet on high heat and spray with olive oil (or avocado oil) when it is hot. Toss in the shrimp and cook for 6 to 8 minutes, continuously shaking the skillet so all sides of the shrimp are cooked and the edges are seared. The shrimp should be plump, solid and pink-ish white. Set the shrimp aside and place the skillet back on the heat.
Spray the skillet with a little olive oil then toss in the frozen corn. Cook for 3 to 5 minutes, or until the outside edges are seared and the corn is warm and completely thawed. Set aside.
Add red onions to a small bowl and squeeze in the juice from 1 lime. Let the onions marinate in the lime juice for at least 8 minutes.
Mix together the ingredients for the dressing and set aside.
Add all the ingredients for the salad together in a larger bowl (minus the lettuce), including the marinated onions (with the lime juice). Fold everything together until well mixed.
Place the salad on a bed of lettuce and drizzle on the dressing! Enjoy