1. Preheat slow cooker to high. Peel and mince onion. Heat a third of the olive oil in a very large saucepan or wok over medium heat.
2. Add the onion, garlic, and salt and sauté, stirring constantly, for about 4 minutes, or until the onion begins to soften.
3. Add the rice to the pot and stir until coated with a nice sheen, then add the white wine and simmer for 3 or 4 minutes, until the rice has absorbed the liquid a bit.
4. Transfer the contents of the pan to the slow cooker with the chicken broth.
5. Reduce heat to low and cook until the rice is tender and most of the liquid has been absorbed, about 4 hours.
6. Meanwhile, chop basil, zucchinis, and tomatoes. Sauté the zucchini in half of the remaining olive oil until it begins to soften.
7. Pan-fry the pancetta.
8. When rice is tender and no liquid remains, stir in the tomatoes, basil, and cooked zucchini and remaining olive oil.
9. Season with salt and pepper to taste.
10. Spoon the risotto into bowls and crumble pancetta over for garnish.