Special equipment: 6-inch skewers, soaked in cold water for at least 1 hour
For the shrimp: Whisk together the chile powder, garam marsala, canola oil, lemon juice in a medium bowl and season with salt and pepper. Add the shrimp and toss to coat in the mixture. Let marinate for 15 minutes.
Prepare a charcoal grill for direct grilling, high heat.
For the chutney: Combine the cilantro, mint, scallions, chile, 1 tablespoon each honey and canola oil, lime zest, and some salt and pepper in a food processor. Process to make a smooth paste. Taste; add honey, if desired, or more oil to make a sauce that will cling to the shrimp.
Thread 2 skewers through 3 shrimp so that the shrimp lay flat. Sprinkle with salt and pepper. Grill until golden brown and slightly charred on both sides and just cooked through, about 1 1/2 minutes per side.
Remove the shrimp to a platter and serve with the cilantro-mint chutney.