Combine the chutney, soy sauce, garlic, vegetable oil, and reserved pineapple juice in a blender container and blend until the marinade is smooth.
Transfer half the marinade to a large resealable plastic bag. Add shrimp; turn to coat with the marinade. Set aside in the refrigerator until ready to grill.
Pour remaining marinade in a small serving bowl or gravy boat, and set aside. (Make sure you only set aside marinade that has not touched the raw shrimp!)
When ready to cook, coat the grill rack with cooking spray. Prepare the grill to medium-high heat. Drain and discard the marinade from the shrimp.
Onto 4 barbecue skewers, spear equal portions of pineapple chunks, tomatoes, and shrimp. Place kabobs on hot grill and cook for 3 minutes on each side, or until shrimp is pink.
Serve extra marinade for dipping.