Cooked white rice, for serving (or cauliflower rice)
Add the red onion, bell pepper, and chickpeas into the bowl of your slow cooker.
In a small bowl, whisk together the tamari, vinegar, maple syrup, garlic, ginger, red pepper flakes, and sesame oil. Pour the sauce into the slow cooker and stir well.
Cover the slow cooker and set it to cook for 3 hours on high heat, or 6 hours on low heat. If you need to cook it longer due to your schedule, I'd recommend adding 2-4 tablespoons of water to the mixture to help prevent the sauce from over-cooking. (If you have a super-nice slow cooker, it might also give you the option to have the cooker start cooking later in the day on a timer.)
Once the cooking is done, give the chickpeas a stir and serve them warm over a bed of white rice (or cauliflower rice) with a sprinkling of green onions and sesame seeds on top.
Leftovers can be stored in an airtight container in the fridge for up to a week.