In a medium bowl, combine the hot water, sugar and salt. Stir with a whisk until the sugar is dissolved. Whisk in the rice vinegar. Add the sliced red onion and jalapeno.
Saute onion and green peppers then add in garlic. Add beef and spices. Stir in tomatoes, Worcestershire sauce, vinegar, brown sugar, sriracha and mustard. Bring to a simmer then reduce heat to low for 20 minutes.
Brush Texas toast with garlic butter then place buttered side down in the skillet. Add one slice of cheese to one slice then the sloppy joe mix on the other slice. Cook until cheese is melty and bread is golden brown.
Top the sloppy joe mix with pickled veggies, flip the slice of bread with the cheese over the top of the meat and remove from pan. Cut Texas Toast Sloppy Joe in half and serve hot.