DIRECTIONS
To prepare rolls, rinse the rice thoroughly in a sieve.
Drain well.
Bring 1 1/4 cups water to a boil in a medium saucepan; add rice.
Cover, reduce heat, and simmer 20 minutes or until liquid is absorbed.
Remove from heat, and let stand 5 minutes.
Stir in ginger, mirin, minced jalapeño pepper, shallots, sugar, fish sauce, and salt.
Combine soy sauce and 1 tsp. sugar.
Brush over tuna.
Marinate in the refrigerator for 10 minutes.
Heat a nonstick skillet over medium-high heat.
Add tuna to pan and cook for 1 1/2 minutes on each side or until desired degree of doneness.
Cut tuna into 8 slices, 1/4-inch thick.
Add hot water to a large, shallow dish to a depth of 1-inch.
Place 1 rice paper sheet in dish.
Let stand 30 seconds or just until soft.
Place sheet on a flat surface.
Arrange 1/4 cup of watercress to cover half of sheet, leaving a 1/2-inch border.
Top with 1/3 cup rice mixture; spread evenly.
Arrange 1 tuna slice over rice.
Fold sides of sheet over filling; starting with filled side, roll up jelly-roll fashion.
Repeat procedure with remaining rice paper sheets, watercress, rice mixture, and tuna.
Cut each roll in half diagonally.
To prepare sauce, combine vinegar and remaining ingredients.
Arrange 2 roll halves on each of 8 plates and serve 2 1/4 tsp. of sauce with each serving.