Preparation Preheat oven to 450°F. Cut potatoes in half lengthwise. Toss with 1 Tbsp. oil, 1/2 tsp. salt, 1/4 tsp. cayenne, and 1/4 tsp. cumin on a rimmed baking sheet. Arrange cut side up and roast until fork-tender, about 25 minutes. Meanwhile, heat remaining 1 Tbsp. oil in a medium skillet over medium. Add onion and half of garlic and cook, stirring, until onion starts to release moisture and turns translucent, 2–3 minutes. Add beans, broth, 1/4 tsp. salt, and remaining 1/4 tsp. cayenne and 1/4 tsp. cumin and cook until liquid is reduced and beans soften, about 10 minutes. Meanwhile, mash avocado and remaining garlic in a medium bowl with a fork until smooth. Stir in 2 Tbsp. cilantro, 1 Tbsp. lime juice, and remaining 1/4 tsp. salt. Add spinach and remaining 1 Tbsp. lime juice to bean mixture. Continue to cook until spinach wilts, about 30 seconds. Using the back of a spoon, gently push down in center of potato halves to create a divot. Spoon bean mixture into potato halves, then top evenly with 2 Tbsp. avocado mixture, quesco fresco, and remaining 1 Tbsp. cilantro. Serve with tortilla chips, if using, and remaining avocado dip alongside. Do Ahead Potatoes and beans can be made 3 days ahead; store separately, cover, and chill. Reheat potatoes in oven and beans in skillet before serving.