These are super fun for company and when serving with grilled items because the patties reheat beautifully in the microwave on medium heat for 30 seconds per side or less. So you can make everything ahead of time, then just microwave the patties first, then the tortillas and simply assemble, rewarm and you're done! :)
*I would not suggest trying to grill these, though. The patties are too soft and would fall through the grates.
**And about the hoisin sauce, I ONLY use Kikkoman brand because I've had very bad luck with other brands. Hoisin sauce should be very DARK in color, sweet and be very thick. Not red, runny, tomato-y and resembling barbecue sauce.
Mini ones can be made as appetizers for parties. Just make sure the tortillas are large enough.