Heat oil in large skillet over medium-high heat. Sprinkle in seeds and cook until aromatic, 10 - 15 seconds.
Add chiles and cook until blackened, 5 - 10 seconds.
Add mustard greens and garlic paste. Stir-fry until moisture evaporates and mixture starts to brown, 8 - 10 minutes.
Add tomato, salt, sugar, turmeric, and garam masala. Cook until tomato softens, 2 - 3 minutes.
Stir in shrimp and 1/4 cup water. Bring to a boil, lower heat to medium, and simmer until shrimp are cooked, 5 minutes.
Stir in coconut and serve.