Bring a large pot of salted water to a rapid boil. Add gluten-free short pasta and cook according to package directions until al dente, about 6-8 minutes. Drain and rinse under cold water, then set aside.

In a mixing bowl, combine unsweetened cashew yogurt, avocado oil mayonnaise, Sriracha, rice vinegar, honey, tamari soy sauce, and a pinch of salt and pepper. Whisk until smooth and creamy.

In a large mixing bowl, add the chilled, drained pasta, diced red onion, diced red bell pepper, and grated carrot. Gently fold together.

Pour the creamy dressing over the pasta and vegetables. Toss everything together until well coated.

Gently fold in the drained tuna, being cautious not to break it up too much.

Transfer to serving plates or a large bowl. Garnish with scallions and toasted sesame. Serve immediately.