Gently pound the tuna slices into 2-inch by 6-inch pieces. Place on plastic wrap. Toss the remaining ingredients in a bowl.
Spread about 4 tablespoons of the lobster mixture to the edges of each piece of tuna. Roll tuna like a sushi roll. Slice roll into pieces 2-inch thick. Drizzle with soy vinaigrette.
Whisk all ingredients together in a small bowl.
In a medium saucepan, toast the curry paste in the olive oil over medium heat for 1 to 3 minutes. Add remaining ingredients. Let simmer for 10 minutes.
Strain into a roasting pan and freeze.
When frozen, scrape granita with a fork to form ice crystals. Serve.
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