Cook broccoli rabe in boiling water in a large Dutch oven 2 minutes or until wilted.
Remove broccoli rabe with a slotted spoon. Rinse under cold water; drain. Reserve 3/4 cup cooking liquid.
Cook pasta according to package directions, omitting salt and fat.
Drain.
Heat oil in a large nonstick skillet over medium heat.
Add leek to pan; cook 2 minutes or until wilted, stirring occasionally. Stir in pepper and garlic; cook 2 minutes, stirring occasionally. Increase heat to medium-high.
Remove casings from sausage.
Add sausage to pan; saute 4 minutes, stirring to crumble.
Add 1/2 cup reserved cooking liquid; cook 5 minutes or until sausage is done.
Add remaining 1/4 cup reserved cooking liquid, broccoli rabe, pasta, and rind to pan; toss to combine. Cook 5 minutes or until thoroughly heated.