Preheat grill to high. In bowl, whisk together, lime zest, juice, 3 tbsp (45 mL) of the honey, garlic chili sauce and salt.
Cut watermelon into 1-inch (2.5 cm) thick wedges. Lightly drizzle each side with remaining honey and place on grill. Grill until just browned, about 2 minutes per side. Place watermelon slices on a plate and drizzle with lime dressing. Garnish with cilantro.
Tip: Garlic chili sauce makes a great marinade for ribs, chicken and shrimp.