Cut 1/2 inch off the top and bottom of pineapple. Slice off rind about 1/4 inch deep, from top to bottom. To remove eyes and make decorative notched edges, use a small knife to cut continuous, parallel, wedge-shaped rows (1/2 in. deep) into the sides of pineapple, following the spiral pattern of the eyes and working from top to bottom. Cut fruit crosswise into 1/4- to 1/2-inch-thick slices; arrange on a platter or plates. Cut limes into halves or wedges. Mix salt with chili flakes and cayenne. Squeeze lime over fruit and offer chili salt to add to taste.