Rinse and drain chard well. Trim off coarse stem ends; then cut stems crosswise into 1/4-inch-wide strips and set aside.
Cover chard leaves and refrigerate.
In a 3-quart or larger electric cooker, combine chard stems,lentils, onion, garlic, cumin seeds, red pepper flakes, and black pepper.
Pour in water. Cover and cook at low setting until lentils are tender when mashed with a fork (6 to 7 hours).
Cut chard leaves crosswise into 1/2-inch-wide strips; stir into cooker.
Increase heat setting to high; cover and cook until chard is wilted and bright green (about 15 minutes more).
Meanwhile, in a 5 to 6-quart pan, cook linguine in 3 quarts boiling water just until tender to bite (10 to 12 minutes); or cook according to package directions. Drain well, pour into a warm wide 4-quart bowl.
Season lentil sauce to taste with salt.
Add lentil sauce and Neufchatel cheese to linquine, mix lightly to coat well.