In medium bowl, combine ground beef, jalapeno pepper and chili powder, mixing lightly but thoroughly.
Shape beef mixture into four 1/2-inch thick patties.
Place patties on grid over medium ash-covered coals. Grill uncovered 14-16 minutes or until centers are no longer pink, turning once. Check with a meat thermometer for an internal temperature of 160°F.
Approximately 1 minute before burgers are done, sprinkle each with 1 Tbsp. cheese.
Place one slice tomato on bottom half of each bun and top with burger. Close sandwiches and serve.
