One-Pot Taco Spaghetti

1 tablespoon olive oil
1 pound ground beef
½ cup yellow onion, diced
4½ tablespoons taco seasoning, or 1.25-ounce package 
1 tablespoon tomato paste
1 10-ounce can diced tomatoes 
8 ounces spaghetti
3 cups of water
½ cup shredded cheddar cheese
½ cup shredded mozzarella cheese
1 Roma tomato, diced
2 tablespoons chopped fresh cilantro leaves