I recommend using fresh or refrigerated pesto, not the shelf-stable jarred stuff.
Slow Cooker Pesto Rice and Beans
1/2 cup brown rice
1 1/4 cup water or chicken broth
1 can Great Northern beans, rinsed and drained
1 cup frozen cut green beans
1/4 cup pesto
1/4 cup Italian style shredded cheese or Parmesan
Pour rice, water or broth, and Great Northern beans into slow cooker. Cook on low for 2 1/2 hours.
Pour in green beans and cook 1 hour more, or until rice and green beans are tender.
Stir in pesto and cheese until cheese has melted.