In a 3 quart bowl, mix salt and sugar with 1 quart cool water until dissolved. Trim the tenderloins of excess fat and silver skin and submerge them in the brine; let stand about 45 minutes at room temperature. Remove the pork from the brinen and pat dry.
In the meantime, make the sweet chili glaze.
For the Sweet Chili Glaze: In a small saucepan (I use my omelette pan) heat the oil, chile powder and cumin over medium heat. When the mixture starts to sizzle and the spices become fragrant, add the pineapple juice. Simmer until the mixture becomes thick. Remove from heat. At this point I like to stir in a tablespoon of mango chutney.
Remove the pork from the brine and pat dry.
Brush the tenderloins all over with the sweet chile glaze and then season with salt and pepper.
Heat a gas grill, turning all the burners to high until the grill is fully heated, 10 to 15 minutes.
Put the pork on the hot grill grate. Turn heat down to 400 degrees. Close the lid and grill for 7 minutes.
Turn the pork over, close the lid, and grill for another 6 minutes.
Turn off the heat (keep the lid closed) and let the pork cook for another 5 minutes. At this point, an instant-read thermometer inserted into the middle of the thickest end of the tenderloin should read 145° to 150°F. (If not, close the lid and let the pork continue to roast in the residual grill heat.)
Remove the pork from the grill and let rest for 5 minutes before carving. Cut across the grain into 1/2-inch slices and serve immediately, Drizzle liberally with Mango Chutney.