Slice the pepper and onion. Put the olive oil in your skillet and preheat slightly, then add pepper and onion slices. Cook on medium heat, stirring every few minutes until they start to get tender (probably about 10 minutes total.)
Meanwhile, peel your shrimp and remove the tails. My husband prefers to use a shrimp deveiner tool, I find it messy and useless. Do what makes you happy.
Also meanwhile, open your can of black beans and drain and rinse them (to remove all the extra sodium that you don't need.) At this point, you can also slice your mango into bite-size pieces, wash and chop your salad greens, and grate your cheese.
When the peppers and onions are tender, toss your shrimp into the pan and season with the garlic powder, sea salt, and other seasonings of your choice. Shrimp cook really fast, so stay here with them and stir them so they cook evenly. They will only take 2-3 minutes before they are done - they will turn pink as they cook. (If you buy pre-cooked shrimp, I would still toss them in for just a minute so they can meld flavors with the peppers, onions, and seasoning.)
To assemble the salad, top the greens with the pepper/onion/shrimp mixture, then add your black beans, mango, coconut lime dressing, and shredded cheese.