6 tablespoon reduces-sodium soy sauce |
1/4 cup (packed) fresh cilantro leaves |
2 tablespoons mayonnaise |
1 tablespoon oriental sesame oil |
2 teaspoons rice vinegar |
1 1-inch piece peeled fresh ginger, chopped |
1/4 teaspoon cayenne pepper |
1 12- to 14-ounce fresh tuna steal (about 1 inch thick) |
2 bunches watercress, stems trimmed |
1 bunch radishes, trimmed, sliced |
sesame seeds |