Bring a large pot of salted water to a boil. Fill a medium bowl with water and add ice. Add the lobster tails to the boiling water and boil until just cooked through, 5 to 7 minutes. With tongs, transfer the lobster to the ice water; retain the cooking water. When cool, drain the lobster tails, crack the shells, and remove the meat. Quarter the meat and set aside.
Return the water in the pot to a boil. Add the shrimp, and cook until just done, 3 to 5 minutes. Check the shrimp after 3 minutes; they must not overcook. Drain the shrimp and transfer immediately to the ice water. When cold, drain on paper towels and peel.
In a small bowl, combine the wasabi, soy sauce, lemon juice, and sugar and whisk to blend. Whisk in the oil to make a light emulsion. In a large bowl, combine the crabmeat, lobster meat, shrimp, mizuna, and tomatoes. Add the dressing, season with the salt and pepper, and toss to blend.
Divide the salad among 4 plates. Garnish with the daikon sprouts and serve.