Move an oven rack so that it is about 5 inches from the broiler. Turn oven broiler on.
Remove core of peppers then cut into large flat pieces. Arrange pepper pieces, skin-side up, on a baking sheet. Broil 5 to 10 minutes until the peppers skin has charred.
After peppers have cooled, gently peel away the charred pepper skin and discard. Reserve 1 to 2 pieces of the peeled roasted pepper pieces to use as a garnish when serving then roughly chop the rest.
In the bowl of a food processor, combine the tahini and lemon juice and process for 1 minute, scrape the sides and bottom of the bowl then process for 30 seconds more.
Add the olive oil, minced garlic, cumin, and a 1/2 teaspoon of salt to the whipped tahini and lemon juice. Process for 30 seconds, scrape the sides and bottom of the bowl then process another 30 seconds or until well blended.
Open, drain, and rinse the garbonzo beans. Add half of the garbanzo beans to the food processor and process for 1 minute. Scrape sides and bottom of the bowl, then add remaining garbonzo beans and process until thick and quite smooth; 1 to 2 minutes.
Add the roasted peppers and continue to process for 1 to 2 minutes or until smooth.
Taste for salt and adjust as needed. Finely chop the reserved peppers. Garnish top with reserved peppers and chives.