De-vein and clean the prawns
Mix chili powder, salt, lemon juice, and turmeric powder with 1 tablespoon of cooking oil in a metal bowl
Marinate the prawns in the mixture
Let rest for 1 hour
While waiting, quarter the bell peppers and remove their seeds
Quarter the tomatoes
Spear the prawns, capsicum, and tomatoes onto the skewers. Alternate as you go
Place on hot grill and cook until well done, turning occasionally to avoid burning them
Serve Immediately