Step 1

In a large bowl, stir together the oil, tomato paste, lemon juice, ginger, garlic, curry powder, turmeric, cayenne, 1¼ teaspoons salt and ½ teaspoon black pepper. Add the chicken and mix with your hands, rubbing the seasonings into the meat, until evenly coated. Marinate at room temperature for about 30 minutes while you prepare the grill or cover and refrigerate for up to 4 hours.

Step 2

Prepare a charcoal or gas grill. For a charcoal grill, ignite a large chimney of coals, let burn until lightly ashed over, then distribute evenly over the grill bed; open the bottom grill vents. For a gas grill, turn all burners to high. Heat the grill, covered, for 5 to 10 minutes, then clean and oil the grate.

Step 3

While the grill heats, thread the chicken, alternating with the pepper and onion pieces, onto 6 to 8 metal skewers. Place the skewers on the grill. Cook without disturbing until lightly charred on the bottom and the meat releases easily from the grill, 3 to 4 minutes. Flip the skewers and cook, turning every few minutes, until charred all over and the chicken is no longer pink when cut into, another 8 to 9 minutes. Transfer to a platter and serve with lemon wedges.