1. Preheat broiler. Put tomatillos on a rimmed baking sheet and broil 2 to 3 in. from heat, turning once, until charred in places, about 12 minutes. Let cool 5 minutes.
2. Pulse tomatillos (including skins) only 4 or 5 times in a food processor with 2 tbsp. cilantro, the zest, and 1/4 tsp. each salt and pepper. Scrape into a bowl; set aside.
3. Pulse garlic, beans, broth, chipotle, and remaining 1/4 tsp. each salt and pepper in a food processor until almost smooth.
4. Spread bean mixture in a small bowl (preferably straight-sided). Spoon red peppers, then tomatillo sauce in layers on top. Spoon yogurt in the middle. Garnish with more cilantro and serve with chips.
Note: Nutritional analysis is per 3-Tbsp. serving.