Ingredients

• 4 Green Thai chiles, stemmed, coarsely chopped
• 1 tablespoon plus 1 teaspoon grated peeled fresh ginger
• 1 tablespoon toasted sesame seeds
• 1 garlic clove, coarsely chopped
• 1/2 teaspoon kosher salt plus more for seasoning
• 1/4 cup sunflower or vegetable oil
• 2 teaspoons toasted sesame oil
• 1 teaspoon distilled white vinegar
• 1 pound sashimi-grade yellowfin tuna fillets, cut into 1/8" cubes
• 4 toasted dried nori sheets, halved lengthwise
• 1 1/2 cups (about) cooked short-grain rice, cooled
• Assorted fillings, such as sliced scallions, English hothouse or Persian cucumbers, cilantro leaves, and chive blossoms
• **Ingredient info:**Look for Thai chiles, nori, and chive blossoms at better supermarkets and at Asian markets.

Instructions

1. Purée chiles, ginger, sesame seeds, garlic, and 1/2 teaspoon salt in a mini-processor until paste forms. Transfer to a medium bowl. Stir in both oils and vinegar. Season dressing with salt. Add tuna; gently toss just to coat.
2. Place nori sheets on a work surface with short side facing you. Spread about 2 rounded tablespoons rice evenly on bottom third of each sheet. Divide tuna mixture among rolls, spooning over rice. Top with fillings. Roll into cones or log shapes, using a few grains of cooked rice as "glue" to seal.