Combine lemongrass, leaves, garlic, galangal, turmeric and water in the blender. Blend until smooth. Combine the zucchini, squash, eggplant and beans in a large stockpot, over medium high heat. Add chicken, spice paste and cayenne, stir constantly for 5 minutes. Add rice powder, fish sauce, salt, sugar and water. Stir well. Cook for 12 minutes. Stir in spinach and remove from heat. Serve with rice.