Fill a large pot with water; pour in the olive oil and salt. Bring to a rolling boil over high heat. Stir in the fusilli, and return to a boil. Cook the pasta uncovered, stirring occasionally, until the pasta has cooked through, but is still firm to the bite, about 9 minutes.
Drain and set aside.
Heat a large skillet over medium-high heat and stir in the ground beef. Cook and stir until the beef is crumbly, evenly browned, and no longer pink.
Drain and discard any excess grease.
Mix in taco seasoning mix, remove from heat, and cool completely.
Combine salsa, ranch dressing, bell peppers, green onions, jalapenos, and black olives in a medium bowl. Toss together the cooked pasta, cooled beef mixture, Cheddar cheese, and dressing mixture in a large bowl. Cover and refrigerate at least 1 hour before serving.
