1Bring a large pot of lightly salted water to a boil; cook the pasta at a boil until tender yet firm to the bite, about 8 minutes; drain and rinse under cold water until chilled.
2Place avocado into a bowl and sprinkle with 2 teaspoons lime juice to prevent browning; cover and refrigerate.
3Toss cooked pasta, shrimp, tomatoes, green onions, red onion, green, red, yellow, and orange bell peppers, and cilantro in a large salad bowl until thoroughly combined.
4Pour vegetable juice cocktail, olive oil, ketchup, and 1/4 cup lime juice into a food processor; add horseradish, jalapeno pepper, hot pepper sauce, salt, garlic, and black pepper. Pulse a few times to mix the dressing, then process until jalapeno and garlic are chopped very small, about 30 seconds. Pour dressing over pasta salad and stir to combine. Cover salad and chill thoroughly in refrigerator, 2 to 3 hours; just before serving, gently stir in avocado.