Chicken Skewers

Ingredients
Spice rub:
1 teaspoon salt
1 teaspoon ground cumin seed
½ teaspoon paprika
¼ teaspoon turmeric
¼ teaspoon cinnamon
¼ teaspoon crushed red pepper flake
2 pounds boneless, skinless chicken breast or thighs
12 large button mushrooms
1 red bell peppers, cut into eighths
1 onion cut into eighths
2 jalapeños, optional