Quarter the cherry tomatoes. Remove the stem and the seeds from the red bell pepper. Finely chop the bell pepper and onion.
Heat olive oil in a large skillet over medium heat. Add tomatoes, bell pepper, and onion with a pinch of salt and the crushed red pepper. Stir to coat everything in the oil, then cook for 7-8 minutes until the vegetables are softened.
Cook the dried pasta shells in boiling salted water until al dente (about one minute less than the package directions.). To time this best, pour the pasta into the boiling pasta water when you add the chorizo to the softened vegetables.
Add the chorizo and garlic, and cook for 5-6 minutes, breaking the chorizo into small pieces as it cooks. Stir in the sugar, then pour in the half & half. Stir the half & half into the chorizo until it is mostly absorbed, then stir in the fresh spinach until it has completely wilted down and mixed into the chorizo sauce.
Use a slotted spoon to transfer the cooked pasta shells directly into the chorizo and spinach sauce, reserving the pasta water. Stir to coat the pasta entirely in the chorizo and spinach sauce, then turn the heat off from under the skillet.
Stir in the parmesan. If you want a creamier pasta, stir in reserved pasta water 1/4 cup at a time until it's as creamy as you like it. Taste the pasta, and season with salt and pepper to taste.
Stir in the freshly squeezed lemon juice, and serve immediately (with more parmesan if you like!)