Combine tomatillo, onion, garlic, and jalapeño together with the oil and 1/2 teaspoon of cumin. Loosely wrap in foil and place on the grill. Cook for several minutes until onions are tender and vegetables are slightly charred.
Remove wrapped vegetables from grill and transfer to a blender with cilantro and lime juice. Pulse until desired consistency (some prefer a slightly chunky consistency).
Add shrimp to the grill and cook for 2 to 4 minutes until shrimp are cooked through. Remove to a plate.
Divide romaine lettuce among 4 bowls. Top with pepitas, pico, queso fresco, avocado, and shrimp. Drizzle with chili verde and serve.