In a large bowl toss together the pimentos, flour, salt, and mustard powder. Set aside.
To the bowl of a food processor add the cheese and butter and blend until almost perfectly smooth. Gradually add the flour mixture until the two are fully incorporated and resembles orange playdough – fun! Form dough into a rough flat rectangle, wrap in plastic wrap, and refrigerate for about one hour.
Set the oven to 350 degrees. Line a large baking sheet with parchment paper.
Sandwich the dough between two pieces of parchment paper and roll into a large rectangle about 1/8-inch thick. Using a fluted pastry cutter (with the crinkly edges) or a pizza wheel, cut the rectangle into long thin straws, about 1/8- to 1/4-inch wide. Carefully transfer the straws to the lined baking sheet, sprinkle with sea salt, place in the middle of the oven, and bake for 12 to 15 minutes or until the crackers are set and the bottoms have just begun to brown. Cool on a wire rack and serve with a crisp beer, or not.