How to Make It
Whisk together brown sugar, salt, and paprika in a large, shallow dish. Add salmon; turn to coat. Cover and refrigerate 1 hour, flipping salmon occasionally.
Meanwhile, stir together yogurt, cucumber, lemon juice, dill, and garlic in a bowl; season with salt to taste.
Preheat grill to medium (350°F to 450°F). Using a spatula, scrape off most of the marinade from salmon; discard marinade. Place salmon on oiled grates; grill, covered, until slightly charred, about 4 minutes per side. Transfer salmon to a platter. Serve with tzatziki, warm pita wedges, and grilled tomatoes.