Put the wheat berries in a medium saucepan and fill the pan with cold water (as if you were making pasta.) Add a big pinch of salt (kosher is fine.) Bring the water to a boil and reduce to a simmer. Cook wheat berries until they are tender, about 50-60 minutes. Drain and transfer to a serving bowl to cool slightly.For the dressing: whisk all ingredients together in a medium bowl and season with salt, cayenne and black pepper to taste. Dip a piece of lettuce in the dressing to taste for seasoning.Combine green onions, radishes and greens with the wheat berries in the serving bowl. Toss with enough dressing to coat lightly.