Place 2 cups water, cabbage, carrot, green beans, bell pepper, and yellow split peas in a pressure cooker; lock lid. Bring cooker up to pressure and cook until peas are tender, 6 to 8 minutes. If your pressure cooker does not have a quick-release function, reduce cooking times slightly as food will continue to cook while pressure releases slowly. Drain and reserve excess liquid; set vegetables aside.
Mix ground coriander, sambar powder, chili powder, and 1/2 teaspoon water in a bowl to create a paste.
Heat vegetable oil in a skillet over medium-high heat; cook and stir cumin seeds and mustard seeds until seeds sputter, about 1 minute; add asafoetida powder. Stir in the sambar paste; cook and stir until thickened, about 1 minute. Season with turmeric, and stir in vegetables. If vegetable mixture is too thick, stir in reserved cooking liquid.
Mix cilantro, coconut, tamarind pulp, brown sugar, and salt into vegetable mixture. Simmer for 10 to 15 minutes more.