Cut the cooked bacon into tiny pieces. If you want to get crispy bacon without the mess, I highly recommend trying them in the air fryer (here is a recipe on how to make it).
Now chop the lettuce, tomatoes, and red onion. Then place them in A large bowl along with the chopped bacon. 
Cook the rotini according to the instructions on the box and rinse with cold water after its done cooking. Drain it in a colander and add it to the salad.
Make the dressing by combining the ranch and mayonnaise together with a whisk.
Pour the dressing over the salad ingredients and give them a good throw toss. Served immediately for optimal crispiness and crunchiness.