Trim fat from meat. Cut meat into 2 inch pieces. Place meat in a 3&1/2 or 4 quart slow cooker. Top with onions. In a medium bowl combine the water, the fish sauce, sugar, vinegar, the five spice powder, and half of the jalepeno peppers. Pour over mixture in cooker.

Cover and cook on low-heat setting for 5 to 6 hours or on high heat setting for 2&1/2 to 3 hours.

Remove meat from cooker, reserving cooking liquid. Transfer half of the meat to an air tight container or freezer container; cover and chill or freeze for another use. Shred or chop the remaining meat; transfer to a medium bowl. Strain cooking liquid. Stir enough of the strained liquid (about 1/4 cup) into shredded meat to moisten.

To serve, divide shredded meat among lettuce leaves. Top with radishes, basil, green onions, and the remaining jalepeno pepper. Drizzle with lime juice. Roll up lettuce leaves. If desired serve with asian chili sauce.