In a bowl, combine the mango, coriander, chilli pepper, garlic, soy sauce, rice vinegar, toasted sesame oil and lime juice.
Keep stored in the fridge for up to 1 week.
In a small bowl, stir together the tahini and sriracha. Add water, 1 tablespoon at a time, until the sauce is smooth and pourable. Cover with plastic wrap and set aside.
Place the tuna on a clean surface and press the sesame seeds gently onto each side of the tuna to adhere.
Heat a large skillet over high heat. Add the sesame oil and when the oil shimmers, add the tuna. Sear the tuna for 1 minute per side. Remove the tuna from the skillet. Let cool slightly, then slice thinly.
To assemble. Divide the rice among bowls and top with sliced tuna, cucumber, carrots, radishes, avocado, and nori. Serve with the spicy sriracha sauce and the mango chimichurri.
Recipe and image provided via www.halfbakedharvest.com