Heat grill to high. Drizzle hearts of palm with oil and season with salt and pepper. Grill for 30 seconds to 1 minute per side until slightly charred and just warmed through. Remove from heat.
Whisk together coconut milk, hot sauce, lime juice, honey, 1 teaspoon salt, 1/4 teaspoon pepper, cilantro, and red onion in a medium bowl. Add the crabmeat, mango, grilled hearts of palm, and mesclun, and toss until well dressed. Mound onto a serving plate and drizzle with more hot sauce, if desired. Sprinkle with torn cilantro leaves and serve.