How to Make It
Slice 1 lemon, 1 orange, and 1 lime crosswise into thin slices. Squeeze juice from 2 lemons, 1 orange, 1 lime, and 1/2 grapefruit over a strainer into a measuring cup to equal about 1 cup juice. Place juice in a medium bowl. Peel and section remaining orange.
Heat a grill pan over high. Add half of fruit slices to pan in a single layer; grill 3 minutes on each side or until lightly charred and caramelized. Add charred fruit slices to juice in bowl. Repeat procedure with remaining fruit slices. Add leek halves to pan; grill 7 minutes, turning to char all sides. Cut leeks crosswise into 1/2-inch slices; add to fruit in bowl. When fruit slices are cool enough to handle, squeeze juice and charred pulp into bowl; discard remains. Stir in oil, mint, honey, and salt.
Add shrimp to grill pan in a single layer in batches; grill 2 minutes on each side or until well marked and done. Place cooked shrimp in a large bowl. Add 1/2 cup leek mixture; toss to coat. Combine 3/4 cup leek mixture and salad greens; toss to coat. Divide greens mixture equally among 4 plates. Top evenly with shrimp and orange sections; drizzle with extra leek mixture, if desired.