1/2 pound tuna, sushi quality, cut into small cubes 1/2 avocados, cut into small cubes 1/4 cup red onion, minced 1/4 cup green onions, thinly sliced 1 tablespoon rice wine vinegar 2 tablespoons soy sauce 2 tablespoons canola oil 1 teaspoon toasted sesame seeds salt and pepper, to tast