| 2 | lb | Yellowfin tuna fillets, chopped fine by hand, removing any sinew |
| 3 | tb | Finely chopped scallion |
| 2 | tb | Freshly grated gingerroot |
| 2 | ts | Dijon-style mustard |
| 1 | tb | Soy sauce |
| | Cayenne, to taste |
| | Salt and freshly ground pepper |
| | Vegetable oil |
| | Spicy wasabi mayonnaise: |
| 1/2 | c | Bottled mayonnaise |
| 1 | tb | Wasabi powder mixed with water to make a paste |
| 1 | tb | Fresh lime juice |
| | PICKLED CUCUMBER GINGER RELISH: |
| 1 | | Seedless cucumber, peeled, cut in half and very thinly sliced |
| 1 | sm | Red onion, very thinly sliced |
| 2 | tb | Finely chopped pickled ginger, available in asian specialty stores and gourmet food shops or 2 tablespoons grated fresh gingerroot |
| 1/4 | c | Seasoned rice vinegar, available in most major supermarkets or 1/4 cup white wine vinegar plus 1 tablespoon sugar |
| 4 | | Brioche rolls or other soft roll |
