Combine ingredients in a small bowl. Mash tamarind paste and mix well with other ingredients. Strain into another small bowl, gently pushing any thick paste and tamarind seeds against the strainer with a spoon or spatula to get as much paste as possible, and to get a smooth consistency. Set glaze aside.;
Prepare grill to medium-hot heat. In a large bowl combine first 7 ingredients mixing gently with hands or spoon. Add cilantro, basil, mint, lime zest, salt and pepper mixing gently with hands or spoon. Form into 6 patties.
Brush grill with toasted sesame oil. Place patties on grill. Cook until brown, about 4 minutes, then turn over. Brush with sesame oil and then baste with glaze. Cook until juices run clear when meat is pierced in the center, about 5 minutes depending on thickness. Toast buns lightly, while patties are cooking on the outer edges of the grill.
Serve placing some watercress (or arugula) the bottom half of the buns, then cooked patties and top with a little more tamarind glaze, cucumber slices, red pepper rings and top half of buns.
Recipe courtesy of Norma Molitor, Austin, TX