In a large mixing bowl, combine the cooked and cooled spaghetti with cherry tomatoes, cucumber, bell peppers, black olives, red onion, fresh parsley, and sunflower seeds or pine nuts (if using).
In a small bowl or jar, whisk together the olive oil, red wine vinegar, Dijon mustard, agave syrup or maple syrup, minced garlic, salt, and black pepper. Adjust the seasonings to taste.
Pour the dressing over the pasta and vegetables. Toss everything together until well coated.
Refrigerate the Vegan California Spaghetti Salad for at least 1-2 hours before serving to allow the flavors to meld.
Before serving, toss the salad again and adjust the seasoning if necessary.
Serve chilled and enjoy this refreshing and flavorful Vegan California Spaghetti Salad!
