Trim and spiralize or julienne the zucchini and set aside.
Heat a heavy bottomed pot over medium heat with 1 tablespoon olive oil. Add the minced onion; stir and cook until soft. Mix in garlic and cook for 30 seconds, then add the sliced smoked sausage. Cook until sausage is browned; about 7 minutes.
Add the red pepper flakes, Italian seasoning and add the zucchini noodles. Toss the noodles and sausage with pasta tongs and cook until zucchini noodles are al dente, 3 to 5 minutes. Do not overcook zoodles at this time or else they will become mushy.
Stir in the halved tomatoes and cook for one minute.
Add chicken or beef stock and cook until the liquids thickens a little; about 1 minute. Adjust seasoning with salt and pepper, add a drizzle of lemon juice, garnish with chopped parsley and lemon slices and serve immediately. Enjoy!