Whisk the canola oil, crushed red pepper flakes, ranch dressing mix, and chili powder together in a bowl.
Divide the saltine crackers evenly into 2 1-gallon-sized sealable bags. Pour the oil mixture evenly over the crackers. Seal the bag and flip to allow the oil mixture to run over the crackers for 5 minutes; flip again. Repeat the flipping every five minutes to evenly coat the crackers for about 1 hour. Remove the crackers from the bags and spread onto large platters. Allow to sit overnight before serving.