For lobster:

• Working with 1 lobster tail at a time, place the lobster with the top shell facing up on a cutting board. Using clean kitchen shears or scissors, cut down the center of the shell, avoiding the meat, until you reach the base of the tail (do not cut through the tail; keep it intact). Turn the lobster over and repeat with the bottom shell, cutting down the center to the base of the tail. Using your fingers, gently spread the shells apart and lift out the meat, keeping the meat attached near the end of the tail. Press the empty shell halves back together and lay the lobster meat on top of the shell.

In a large frying pan, bring ½ inch of water to a boil. Add the lobster, with the shell down and meat facing up, cover, and cook until the lobster meat is opaque throughout, 4 to 6 minutes. 

For shrimp:

• Rinse and drain the shrimp. Pat dry on a paper-towel-lined plate. Season lightly with salt and pepper.

In a large frying pan over medium-high heat, warm 2 to 3 teaspoons oil until hot but not smoking. Add the shrimp and cook, turning once, until firm and cooked through, 2 to 3 minutes per side. 

For scallops: 

• Rinse and drain the scallops. Pat dry on a paper-towel-lined plate. Season lightly with salt.

In a large frying pan over high heat, warm 2 to 3 teaspoons oil until hot but not smoking. Add the scallops and cook without turning until golden brown on one side and starting to turn opaque, 2 to 4 minutes. Turn and continue cooking for about 30 seconds for translucent or 1 to 2 minutes for opaque.

Transfer the seafood to a cutting board and let cool slightly. While the seafood is cooking and cooling, prepare the corn and shishito peppers.

• Shuck the corn. Lay the ear flat on a cutting board. Cut lengthwise down one side to remove the kernels, then rotate the ear so the shaved side is on the bottom; continue cutting away the kernels on the remaining sides.

In a dry large frying pan over high heat, add the corn and cook, stirring occasionally, until just tender and lightly browned, 3 to 5 minutes. Transfer to a large bowl and season to taste with salt and pepper. Do not clean the pan. 

In the same pan used for the corn, warm 1 to 2 teaspoons oil over medium-high heat until hot but not smoking. Working in batches if needed, add the shishito peppers and cook, turning regularly, until shiny and starting to char and blister, 4 to 6 minutes. Transfer to a cutting board, season with salt and pepper, and let cool slightly. Add more oil between batches if needed. While the peppers are cooking and cooling, prepare the remaining ingredients.

• Trim the root ends from the scallions; thinly slice the scallions, keeping the white and green parts separate.
• Trim the root end from the lettuce; separate the leaves.
• Cut the avocado in half lengthwise. Remove the pit, scoop out the flesh, and cut the flesh into ¼-inch-thick slices. Season with salt and pepper.
• Cut the nectarine in half and remove the pit; cut the fruit into ¼-inch-thick slices.
• Coarsely chop the pistachios.

• Remove the lobster meat from the shells (if using shrimp, remove the tails). Chop the seafood into ½-inch pieces. 
• Remove the stems from the shishito peppers; cut the peppers into ½-inch pieces.

To the bowl with the corn, add the seafood, shishito peppers, white parts of the scallions, and half the “creamy” dill dressing and toss to coat (set aside the remaining dressing for serving). Season to taste with salt and pepper.

Arrange the lettuce leaves on individual plates, laying them flat to cover the plates. Fan the avocado and nectarine slices over the lettuce. Spoon the salad in the center of the plates and garnish with the pistachios and green parts of the scallions. Serve the remaining dressing on the side.