In a 1-gallon re-sealable plastic bag, combine the tequila, orange juice, garlic, oregano, cayenne pepper, salt, 3-4 grinds pepper. Seal the bag and shale to dissolve the salt. Add the oil and shake again. Add the shrimp to the marinade and re-seal the bag. Massage gently to coat the shrimp with the marinade. Set the bag on a plate and refrigerate for 30 minutes, turning the bag over twice during that time. Set a skillet over medium-high heat. Transfer the shrimp and marinade sauce from the bag to the skillet. Stirring occasionally, cook until the shrimp look pink (approx. 3 minutes). Add the onions and peppers and cook, stirring, until the onions are translucent (approx. 3 minutes). Add the tomatoes (with their liquid) and the Sweet’N Low® zero calorie sweetener. Stirring occasionally, cook until the shrimp are done (approx. 5 minutes). To serve, divide Tequila Shrimp among 4 dinner plates. Garnish with the cilantro, if desired. Serve immediately.