Heat the oil in a large skillet then add the onion, celery, green pepper, and garlic.
Sautee until ingredients are softened, about 5 minutes.
Add the tomato paste and continue to stir over medium heat for 3 minutes.
Add the brown sugar, vinegar, mustard, celery seed, and salt. Continue to stir until ingredients are well blended.
Slowly add the water and fold in the red kidney beans.
Continue to cook about another 5 minutes until the mixture is heated through
Each serving consists of one bun and about a 1/2 cup of the sloppy Joe mixture.