Stir the mayonnaise, lime juice, cumin, chili powder, and salt together in a small bowl.
Coat the bottom of a medium skillet with the olive oil and place it over medium heat.
Give the oil a minute to heat up, then add the onion when it starts to shimmer. Sweat the onion for about 5 minutes, until it begins to soften.
Stir in the garlic. Cook the garlic with the onion, stirring frequently, for about 1 minute, until it becomes very fragrant.
Raise the heat to medium-high and add the corn. Let the corn cook for a minute or two, then flip it. Continue cooking the corn like this, letting it sit on the hot surface for a minute or two at a time and flipping, until it begins to darken in spots. This should take about 5 mintues.
Carefully pour the mayonnaise mixture over the corn. Stir it in and cook the mixture for 1 to 2 minutes to reduce the sauce a bit.
Remove the skillet from heat. Season the mixture with additional salt to taste and black pepper. Stir in the cilantro.
Spoon a bit of refried beans into each tortilla, then top the beans with the corn mixture. Add additional toppings of choice. Serve.