Preheat broiler, with a rack in upper third. Beat eggs with 1/2 teaspoon salt and 1/4 teaspoon pepper until combined.

Heat 2 tablespoons oil in a medium (10-inch) nonstick skillet over medium-high. Add beans and cook, stirring, until lightly charred and crisp-tender, 5 to 6 minutes. Season with salt and pepper. Add shallot and corn; cook, stirring, until vegetables soften, 2 to 3 minutes. Add eggs; stir with a wooden spoon until large curds form and edges just begin to set, about 30 seconds.

Transfer skillet to oven; broil until puffed and browning in spots and eggs are just set, about 2 minutes. Let stand 5 minutes before slicing. Meanwhile, toss tomatoes with remaining 1 tablespoon oil, vinegar, and parsley; season with salt and pepper. Serve salad with frittata.