Step 1Heat a grill over medium high heat until hot. Brush each of the watermelon slices on both sides with olive oil. Grill the slices until barely softened with defined grill marks, about 2 minutes on each side. Remove from heat. Place 1 slice on each serving plate. Drizzle over a little lime juice and honey, then top with a dollop of yogurt. Sprinkle over a little lime zest and mint leaves. Serve immediately.