Take a trip along the Mekong River with a visit to Somtum Der in the East Village where Thai food comes alive with fresh herbs and spices.  Somtum salads made with crisp, julienned green papaya get a jolt from a sweet chili sauce.  The salads come in eight different varieties.  Grilled catfish stars in a soup of enoki mushrooms, basil and kaffir lime leaves.  Wide noodles can be found intermingling with ground pork and crispy basil leaves.  Skewers of pork marinated in coconut milk arrive fresh off the grill with a sweet-and-spicy dipping sauce.  Sundried beef is deep fried and served with a smattering of coriander seeds.  The flavors Somtum Der can be intense and are worthy of a food adventure.