Prepare rice according to package directions. While the rice is still warm, mix in the rice vinegar, sugar, and salt. Let cool slightly.
In a blender, add pineapple, sriracha and 1/2 tsp of rice wine vinegar. Blend until smooth. Set aside.
Pat tuna dry and place the on a clean surface and press the sesame seeds gently onto each side of the tuna to adhere.
In a large skillet, heat sesame oil over high heat. Add the tuna. Sear the tuna for 1 minute per side. Remove the tuna from the skillet. Rest for 1 minute, then slice thinly.
Divide the rice between bowls. Assemble the bowl by first adding the rice. Top with tuna, avocado, cucumber, radish, carrots, edamame, nori. Drizzle with spicy pineapple sauce, and sprinkle with furikake.