Soak skewers in warm water while you fix the marinade.
In a medium sized bowl add all of the ingredients except for the pineapple and shrimp. Whisk to combine. Add the shrimp to the marinade and cover the bowl and then place it in the refrigerator to marinate for at least 10 minutes.
While the shrimp is marinating, heat the grill pan and spray with cooking spray.
Grill pineapple for about 8 minutes, turning the pineapple over every few minutes to get a little char on each side.
While the pineapple is cooking skewer the shrimp. Pour the leftover marinade into a small saucepan and boil the marinade for at least 2-3 minutes, then reduce the heat to simmer to allow the marinade to reduce by half. After the marinade has reduced into a sauce, remove the pan from the burner.
After the pineapple is finished cooking, grill the shrimp for 4-5 minutes, flipping halfway through the cook time. To serve, remove the shrimp from the skewers. Place the grilled pineapple and shrimp over the rice or grains and spoon the sauce on top.