In a large bowl, mix the lemon juice, mayonnaise, vinegar, mustard, sugar, salt, and pepper. Stir in the shrimp, celery, and scallions. Serve on mini brioche buns or regular brioche buns cut into quarters.

FOR THE POTSTICKERS
In a food processor, pulse shrimp until ground. Transfer to a mixing bowl. Add the scallions, egg, salt, and pepper, and using your hands, mix thoroughly. Place 1 level teaspoon of the shrimp mixture onto each wonton. Brush the edge with water and fold into a half moon to seal. Cover with a damp paper towel. In a large skillet, heat 2 tablespoons of the oil over medium high heat. Add half of the dumplings and cook 2 minutes. Add 2 tablespoons water, cover, and let steam 3 to 4 minutes. Cook the dumpling a few minutes longer with the lid off if they are sticking to the pan. Repeat with other half of dumplings.

FOR THE DIPPING SAUCE
Whisk the soy sauce, lemon juice, ginger, barbecue sauce, and sesame oil. Stir in the scallions.

FOR THE BRINE
Combine the hot water, salt, and sugar in a large bowl. Stir until the sugar and salt dissolve. Add the cold water. Cut the lemons in half, squeeze the juice into the bowl, and add the lemons as well. Stir in the garlic, thyme, rosemary, and ice.

FOR THE SHRIMP
Working quickly, use a paring knife to cut along the curve of the back of the shrimp. Keep the shells intact. Remove the vein inside the shrimp and rinse gently with cold water. Place the shrimp in the brine as you go. Refrigerate the shrimp in the brine for 1 hour.

Brush the grill with oil and heat to medium. Combine the red pepper flakes and boiling water. Drain and discard the water. In a large bowl mix the olive oil, lemon juice, rehydrated red pepper flakes, and chives. Set aside.

Remove the shrimp from the brine and dry with paper towels. Toss the shrimp in the canola oil. Place the shrimp on the grill and cover with the lid. Grill for 4 minutes. Turn the shrimp and cook another 4 minutes, until opaque. Remove from the grill and add to the olive oil mixture. Toss to coat and season with salt and pepper to taste. Serve with cocktail sauce and lemon wedges on the side.