Bodhisattva's BBQ Tempeh Kebobs

1 medium bell pepper, 1” chop
1/2 medium red onion, quartered
6-8 medium cherry tomatoes
1 large portabello mushroom, 1” cubes BBQ Sauce:
1/4 cup barley malt syrup
1/4 cup natural catsup
2 tablespoons safflower oil
2 teaspoon apple cider vinegar, raw
2 teaspoon vegetarian Worcestershire sauce
1 teaspoon stone ground mustard
1/2 teaspoon chili powder
1/2 teaspoon paprika
1/4 teaspoon liquid smoke (optional)
pinch cayenne pepper, or to taste