Shrimp Salad, Lime, Avocado & Grapefruit​

From limes, grate 1/4 teaspoon peel; squeeze 1/4 cup juice. Set peel aside. In 1-quart saucepan, heat ginger, sugar, and lime juice to boiling on high, stirring. Remove from heat and let stand. With knife, cut peel and white pith from grapefruit; discard. Holding grapefruit, 1 at a time, over medium bowl, cut out segments between membranes. Squeeze membranes to release remaining juice into bowl. Discard seeds. Thinly slice half of mint. Preheat grill pan or prepare outdoor grill for direct grilling on medium-high.
Rub oil all over shrimp. Sprinkle sliced mint, lime peel, cayenne, and 1/8 teaspoon salt all over shrimp. Grill 3 to 4 minutes or until shrimp just turn opaque throughout, turning over once. Pour ginger mixture through sieve over grapefruit, pressing on ginger to extract liquid. Gently stir to mix. Divide lettuce and mint leaves among 4 plates. Top with shrimp, avocado, and grapefruit mixture. Serve with rolls.

2 limes
1½ tbsp. chopped peeled fresh ginger
1 tbsp. sugar
2 Ruby Red or Rio Star grapefruit
¼ c. packed fresh mint leaves
1 tsp. extra virgin olive oil
12 oz. peeled deveined shrimp (16- to 20-count)
1 pinch cayenne pepper
1 head butter lettuce
1 avocado

4 whole-grain dinner rolls