Heat half the oil in a large skillet over medium-high heat until hot. Add half of the garlic; cook 30 to 60 seconds or until fragrant. Add shrimp, cook 2 to 4 minutes or until shrimp turn pink, stirring frequently. Remove shrimp from pan and keep warm.
Heat remaining oil in the same skillet over medium-high heat until hot. Add onion, red bell pepper and green bell pepper; cook two to three minutes or until onion just begins to soften. Add remaining garlic; cook 30 to 60 seconds or until fragrant. Stir in tomatoes, cucumber, vinegar, saffron, salt and cayenne pepper; cook 2 minutes or until heated through and tomatoes begin to release juices. Stir in shrimp; cook 1 minute or until heated through. Stir in cilantro.