Heat oven to 325° F. In a medium bowl, beat the eggs, half-and-half, ¾ teaspoon salt, and ¼ teaspoon pepper until combined.
Mix in the ham, asparagus, and Gruyère. Pour into the prebaked piecrust and bake until set, 50 to 60 minutes.
Meanwhile, in a large bowl, whisk together the oil, vinegar, ½ teaspoon salt, and ¼ teaspoon pepper. Add the greens and tomatoes and toss to coat. Serve with the quiche.