Oahu's shrimp trucks are the famous hidden gem of the North Shore. Three years ago we have sampled the fares from three of them, and decided that it was the best food we had in Hawaii.
Now, we are on Maui. No North Shore shrimp farms, but, fortunately, there is a shrimp truck:
Found it by googling "Maui Shrimp Truck". Yelp has a bunch of reviews and an address. Google Maps screws the "address" (how can a actual moving truck, and this one is an actual moving truck, have a street address)... The truck is located a couple hundred meters north of the intersection, right next to the entrance to the harbor.
We had two shrimp dishes of the four on the list: the scampi and the spicy pineapple (the other two are hot and spicy and lemon and pepper). The proprietor made the spicy pineapple not too spicy at our request.
The key drawback of the place is the lack of any tables to consume the food. The harbor has two tables next to the boat drop-off point. It is quite windy there though, we had to hold the food boxes with cans of soda.
The shrimp is cooked in the same style as in Oahu: each dish is a dozen non-shelled shrimp, but the recipes were different. The scampi sauce did not have the mass of bread crumbs and garlic chunks like the Oahu scampi. The sauce was clear, a bit caramelized and, I guess, somewhat healthier than what you'd get a Giovanni's or Famous Kahuku... (-: Spicy pineapple sauce was similar in structure, had pineapple chunks in it and had a slight kick - I am guessing it'd be much spicier if ordered unmodified. The shrimp in both dishes was juicy and extremely tasty. The rice was ok, but became tasty only after being soaked in the sauce. The crab macaroni salad was excellent in my opinion, although I was the only one who ate it.
Overall a good experience. A very nice proprietor (asked us where we were from and how we found out about him), decent prices ($11 per main dish) and great food. Skip the luau, get some some Geste shrimp!