Heat gas or charcoal grill. In 1-quart saucepan, mix 1 tablespoon of the bourbon, the teriyaki glaze, orange juice concentrate, brown sugar and crushed red pepper. Heat to boiling over medium heat; reduce heat to low. Simmer 5 minutes, stirring occasionally; remove from heat. Stir in remaining 1 tablespoon bourbon. Reserve 2 tablespoons glaze.
In medium bowl, place beef, onion, mushrooms and bell pepper. Drizzle with oil; toss to coat. Sprinkle with salt; toss to coat. On each of two 10- to 12-inch metal skewers, thread beef, onion, mushrooms and bell pepper alternately, leaving 1/4-inch space between each piece.
Cover and grill kabobs over medium heat 9 to 11 minutes, turning once and brushing with glaze during last 3 minutes, until beef is desired doneness and vegetables are tender.
Just before serving, generously brush kabobs with reserved 2 tablespoons glaze.