How to Make It
Preheat the oven to 350°. Put the hazelnuts in a pie plate and toast them for 8 minutes, or until they are golden brown. Let cool, then rub the nuts together in a kitchen towel to remove the skins. Transfer to a work surface and coarsely chop the hazelnuts.
Bring a large pot of water to a boil. Add the ears of corn and boil them over moderately high heat until just tender, about 4 minutes. With tongs, transfer the corn to a rimmed baking sheet. When cool enough to handle, cut the kernels from the corncobs.
Add the green beans to the pot and boil until crisp-tender, about 3 minutes. Drain and rinse the beans under cold water. Pat dry. Cut the beans into 1-inch lengths.
In a large bowl, mix the olive oil with the vinegar and season with salt and pepper. Add the tomatoes, scallions, corn and beans and toss. Sprinkle with the hazelnuts and serve.