How to Make It
Combine first 4 ingredients in a microwave-safe bowl; microwave at HIGH 45 seconds or until smooth.
Heat a medium skillet over high heat. Add oil to pan; swirl to coat. Add tuna to pan; cook 2 minutes on each side for medium-rare. Place tuna on a cutting board. Let stand 5 minutes. Cut across the grain into thin slices; sprinkle with salt.
Add warm water to a large shallow dish to a depth of 1 inch. Place 1 rice paper sheet in dish; let stand 30 seconds. Place rice paper sheet on a dry kitchen towel. Place one-fourth of tuna on bottom third of sheet, leaving a 2-inch border. Top with 2 avocado slices, 1/4 cup carrot, and 2 tablespoons cucumber. Fold bottom of sheet over filling. Fold sides of sheet over filling; roll up, jelly-roll fashion. Gently press seam to seal. Place roll, seam side down, on a serving platter. Repeat procedure with remaining wrappers, tuna, avocado, carrots, and cucumber. Serve with pineapple mixture.