After shucking the corn, strip the kernels from the cob. To do this, stand the cob up in a shallow bowl and cut down as many times as needed to remove all the kernels. Slice the tomatoes into wedges or chop them into bite-sized pieces.
Turn the pan up to high heat and add the oil and the corn. Cook for about 2 minutes undisturbed, then stir it around to make sure each kernel gets a little color. Add the onions, garlic, jalapeño, and tomatoes and stir well. Cook another 3-5 minutes or until everything has softened just a little.
Remove from heat and add salt & pepper to taste, and mix in the lime juice. When ready to serve, stir in the avocado and place over fresh greens, like romaine, spinach, or arugula.