Coat a large saucepan generously with olive oil over medium heat. Add the onions and salt and sweat until translucent, about 5 minutes. Bring the pan to a medium-high heat. Add the rice and cook, letting the rice slightly stick to the bottom of the pan and scraping it off, until it sounds crackly, 3 to 4 minutes.
Add the wine to the pan until it covers the surface of the rice. Season with salt and cook over medium-high heat, stirring continuously, until the wine has absorbed into the rice. Add the chicken stock to the pan until it covers the rice, about 4 minutes. Cook over medium-high heat, stirring continuously, until the stock has absorbed into the rice, about 6 minutes.
Repeat this process two more times with the hot chicken stock. When the third addition of the stock has absorbed and the rice is very creamy, bite a couple grains of rice to test how it is cooked. Add the squid ink and mix to incorporate. If the rice is still a little crunchy, add a little more stock and cook the rice for another couple of minutes. Add the calamari and allow to cook until tender and the rice is creamy but still flows and holds its own shape, 5 to 7 minutes. When the rice is cooked perfectly, remove it from the heat.
Toss in the butter and Parmigiano-Reggiano and fold to combine. Garnish with chives or micro bull's blood if using, and a big glug of good extra-virgin olive oil.