Use a 2 to 3 inch round cutter and cut out 16 circles from 4 tortillas.
In a small bowl mix brown sugar, lime juice, rum and seasoning. Add shrimp and stir to coat. Let sit for 15 minutes.
In a small bowl toss coleslaw with lime juice and olive oil.
Skewer shrimp and grill 1 to 2 minutes each side. Place tortillas on grill for about 1 minute per side. Place pineapple, red onion and avocado on a grill pan and cook until slightly browned.
Place a small amount of coleslaw on tortilla and top with pineapple, avocado and red onion. Top with shrimp and sprinkle with cilantro.
Chop everything up earlier in the day and keep refrigerated.
Make an large tostado by grilling 4 tortillas and topping with a fourth of the toppings.