- Arrange squash in single layer in microwave-safe dish; add 1/2 cup water. Cover and microwave on High 7 minutes, rotating dish after 4 minutes. Drain squash; cool.
- Meanwhile, cut beef into 1-inch squares and bell pepper into 18 pieces; place with squash in large plastic bag.
- Combine teriyaki sauce, oil, vinegar, bay leaves, garlic and oregano; pour into plastic bag. Press air out of bag; close top securely. Turn bag over several times to coat all pieces well. Marinate 30 minutes; turn bag over frequently.
- Thread beef and vegetables alternately on skewers, leaving space between pieces. Discard marinade.
- Grill or broil 5 inches from hot coals or heat source 4 minutes on each side (for medium-rare), or to desired degree of doneness.