They are hotdog sliders with sesame seed buns, made to resemble Krabby Patties.
Role in the episode
After being fired from his job at the Krusty Krab by Mr. Krabs all because of a nickel, SpongeBob enters a state of depression and is advised by Sandy to go find a new job. Taking her advice, the first job he applies for is a fry cook at the hotdog restaurant Weenie Hut. Due to his obsessive attachment to his previous occupation, SpongeBob struggles to adapt to the bizarre nature of this restaurant and winds up making a hotdog that strongly resembles a Krabby Patty. Since the founder, Mister Weiner, doesn't find him competent for the job, he throws the weenie patties on the ground and demands that SpongeBob leave his restaurant to go find a job elsewhere.
However, later in the episode, Weenie finally hires him on grounds that the customers turn out to love his Weenie Patties and demands SpongeBob to make more of them, only for this turn out to be a scam in which he handcuffs him to the grill to benefit his restaurant's businness.