Combine onion, zucchini, cauliflower, and green chili in a small bowl; set aside.
Combine chickpea flour, cornstarch, turmeric, cardamom, cumin, carom, and fenugreek leaves, if using, and salt in a large bowl and mix to combine. Slowly add water, mixing with a whisk to combine. Add more water as needed (mixture should be like pancake batter); set aside.
Pour oil to about 1/2 inch in a large cast iron skillet. Heat oil until shimmering and just before it starts to smoke. You can also use a deep-fry thermometer; let oil rise to 350°F.
When oil is ready, combine vegetables with batter and gently lower large tablespoonfuls of mixture into the hot oil, being careful not to splatter hot oil.
Let cook for a total of 5 to 6 minutes, turning once during the cooking process. If they start to brown too quickly, turn down the heat a bit. Drain pakoras on paper towels and sprinkle with finishing salt. Serve immediately with lime wedges, cilantro, and Sukhi’s Mango Chutney.