Heat a grill pan until smoking hot and place the ear of corn in it dry. Turn it a quarter turn every two minutes until all sides are charred black in spots, about eight minutes in total. Those charred spots are not burnt bits but concentrated flavor: the moisture in the kernels evaporates and their sugars caramelize, giving the corn a depth that boiling can never achieve. Let the cob cool and slice the kernels off the cob with a knife.
Dice the tomatoes and discard the watery seeds. Finely mince the red onion and slice the red chili pepper into thin rings. Mix everything with the corn, two tablespoons of olive oil, the juice of half a lime, the cumin, and salt. Gently fold in the diced avocado just before serving so it stays intact.
Boil the green beans for five minutes until tender-crisp, plunge them into cold water to stop the cooking, and pat them dry. Sauté them briefly in a tablespoon of olive oil with salt.
Pat the swordfish dry, rub it with the remaining olive oil, and season with salt. Grill for three minutes per side. Swordfish is lean and firm and will dry out instantly if cooked even a minute too long, so remove it from the heat as soon as the center is just opaque.
Serve the steak with the salsa, green beans, cilantro, and lime.