1. In a blender, combine the ginger, lemon juice, vinegar, the chopped scallions, the soy sauce, oil, and 1/4 teaspoon of the salt. Blend until smooth, then stir in the lemon zest. Cut the avocado into 1/2-inch dice and add to the scallion vinaigrette.
2.In a large pot of boiling, salted water, cook the linguine until just done, about 12 minutes. Drain the pasta and toss it with the vinaigrette and avocado and the remaining 1/2 teaspoon salt. Gently fold in the crabmeat. Sprinkle with the sliced scallion tops. Serve warm.
Test-Kitchen Tip: As soon as the avocado is diced, put it into the vinaigrette. The acidity of the lemon juice and the vinegar will keep the avocado from browning if dinner is delayed.
Wine Recommendation: An acidic white wine is best with both the tart vinaigrette and the rich avocado. A white from the Loire region in France such as Sancerre (sauvignon blanc grape) or Savennières (chenin blanc grape) is a good choice.