In a blender, combine the anchovies, garlic, and lemon zest. Pulse to chop.
Add the mint, oil, lemon juice, salt, and pepper and blend until smooth.
In a large pot of boiling, salted water, cook the shrimp until they just turn pink, 2 to 3 minutes.
Drain the shrimp and transfer them to a medium glass or stainless-steel bowl. Toss the shrimp with half the dressing.
Put the lettuce in a large glass or stainless-steel bowl and toss with the remaining dressing.
Put the greens on plates; top with the shrimp.
Variations:: Grill the shrimp instead of boiling them. Large shrimp will need about three minutes per side.: Substitute large sea scallops, either grilled or sauted, for the shrimp.
Wine Recommendation: The refreshing flavor of this salad requires a similarly refreshing wine. For a nice, cool accompaniment, choose a light, herbal sauvignon blanc from Italy's Alto Adige or Collio regions.