Add 1 cup of rice and 2 cups of water to a small saucepan. Bring to a boil over high heat (with the lid on), then reduce the heat to low and simmer until all the water has evaporated and the rice is cooked (adding more water if necessary).
Add the spring onions to a small bowl with the vinegar and a pinch of salt. Top with water to cover the onions. Set aside to marinate.
In a separate small bowl, stir together tahini, 1.5 tablespoons of soy sauce, sugar, and sriracha.
Heat oil in a large frying pan over medium-high heat. Add zucchini and mushrooms and cook (with the lid on) for 5-7 minutes, or until softened. Add the carrot and continue to cook for a further 2-4 minutes. Season with salt and pepper. Remove from the pan and set aside.
Add garlic and ginger to the pan and cook until fragrant, about 30 seconds. Add the beef mince, breaking it up, and cook for 5-7 minutes, or until just cooked through. Add the remaining soy sauce and cook for a further 1-2 minutes, or until mostly evaporated.
Divide the rice between bowls. Top with the zucchini mixture and beef. Drizzle with sauce and top with spring onions. Add extra sriracha if desired. Enjoy!