Coleslaw:

Whisk together the vinegar and sugar, in a large bowl, until the sugar dissolves. Add the onion, mustard, celery seed, celery salt and salt and pepper, to taste. Slowly whisk in the oil until emulsified. Add the cabbage and carrot and toss to combine. Let sit at room temperature for 15 minutes before serving.

Relish:

Heat a grill to high.

In a medium bowl toss the tomatoes in canola oil and season with salt and pepper, to taste. Grill until charred and softened. Remove them to a bowl, and add the garlic, onion, olive oil and thyme and season with salt and pepper, to taste. Let sit at room temperature for 30 minutes before serving.

Sandwich:

Heat a grill to high.

Brush the potato slices with oil on both sides and season with salt and pepper, to taste. Grill on both sides until lightly golden brown and just cooked through.

Brush the steak on both sides with oil and season with salt and pepper, to tastes. Grill until golden brown and charred on both sides and cooked to medium-rare doneness, about 6 minutes per side. Remove the steaks from grill to a cutting board and let rest 10 minutes before cutting into thin slices.

Put the sliced meat on aluminum foil and top with slices of the cheese. Put back on the grill, close the cover and cook until the cheese just begins to melt, about 45 seconds. Mound meat on the bottom of the bread and top with potatoes, tomato relish and coleslaw. Cover with the top of the bread and serve.