In a large bowl soak the garlic and onion in the lime juice. Set aside.
Brush the corn with oil and grill or sear in a pan until just charred and getting tender, around 10 minutes.Let it cool then cut the kernels off the cob and set aside.
Combine the mayonnaise and chili powder into the garlic and onion bowl. Mix well. Then put the corn and cheese into that same bowl.Season with salt and pepper and hot sauce if using.Taste and adjust seasoning.
For the scallops you can use a grill, grill pan or cast iron skillet. Brush the scallops on both sides with the vegetable oil and season with salt and pepper.Grill or sear until you get a nice brown crust on you scallop. Depending on the thickness of the scallop it could be about 3 minutes on one side and 2 on the other.I always get a “test” scallop that I cook first to gage how long to cook them. You don’t want to overcook them, they become rubbery.Scallops should be just barely cooked through.
To serve, divide the corn mixture onto 4 plates, place the scallops on top and sprinkle with cilantro (optional) and serve with the lime wedges.