If using dried chickpeas, drain soaking water, rinse, and pressure cook with fresh water, ½ tsp salt, and a pinch of baking soda for 3-4 whistles on high, then 10 minutes on low; allow pressure to release naturally for 15 minutes. If using canned chickpeas, drain, rinse, and pat dry — they are ready to use immediately.
Peel and quarter the potatoes, then boil in salted water for 12-15 minutes until fork-tender; drain and spread on a plate to steam dry for 5 minutes. Once cool enough to handle, cut into ½-inch (1.2cm) cubes — do not mash — and set aside.
Combine all-purpose flour, whole wheat flour, and salt in a large bowl; rub in the oil with your fingertips until the mixture resembles coarse breadcrumbs, then add water gradually to form a firm, smooth dough. Knead firmly for 5-7 minutes, cover with a damp cloth, and rest for 20 minutes.
Divide the rested dough into 10 equal portions and roll each into a thin circle about 5-6 inches (13-15cm) in diameter, roughly 2mm thick. Press a small inverted steel katori into the center and drape the dough up over the sides, pressing firmly and trimming any excess below the rim.
Heat frying oil to 320-330°F (160-165°C) and carefully lower each dough-covered katori mold into the oil, dough-side down, holding it submerged for 2-3 minutes until the dough sets; wiggle the steel mold free and continue frying the bowl for another 2-3 minutes until uniformly golden brown. Drain on paper towels and cool completely before filling.
In a large bowl, combine the cubed potatoes, drained chickpeas, red onion, cucumber, tomato, green chilies, and cilantro; add chaat masala, roasted cumin powder, red chili powder, black salt, and lemon juice and toss gently until evenly combined. Taste and adjust seasoning — the filling should be boldly flavored before assembly.
Whisk the full-fat yogurt vigorously in a small bowl until completely smooth and creamy with no lumps. If the yogurt is very sour, stir in a pinch of sugar to balance; keep refrigerated until assembly.
Fill each cooled katori with 2-3 tablespoons of the filling, then drizzle with whisked yogurt, tamarind chutney, and green chutney; sprinkle with chaat masala, roasted cumin powder, and red chili powder. Top with thin sev and pomegranate seeds as the very final step, then serve immediately.