To make the sauce, combine the hoisin, maple, smoked paprika, chili flakes, onion powder, garlic powder, salt, pepper and olive oil in a bowl, and stir to combine. Set aside.
Slice the halloumi in half through the centre of the block where there is a natural fold - it should fall apart easily - so you have 2 rectangular slabs from each block. Slice each slab into 4 long pieces (we want them to be a similar size to the shishito) - there should be 16 pieces.
Thread the halloumi and shishito alternately onto the skewers - since there are 16 pieces each of halloumi and shishito, skewer 4 of each onto each stick. (If you are feeding 5 like me, you can stretch it out to skewer another stick).
Set the grill to medium high, about 400˚F / 200˚C. Line a baking sheet with parchment paper. Carefully transfer the skewers onto the sheet and drizzle both sides with a little olive oil. Grill (broil) until blistered in parts, 4 to 5 minutes. Carefully flip the skewers over and grill (broil) the other side for 4 to 5 minutes.
Remove from the oven and immediately brush both sides of each skewer with the sweet and smokey sauce. Leave for 2 minutes before serving.