Herb Marinade: In a blender, combine first-listed cilantro, oregano, brown sugar, first-listed lime juice and olive oil. Blend on high speed to make a thick and smooth purée. Keep refrigerated until ready to use. Place chicken breasts in a bowl. Pour marinade over chicken breasts coating evenly. Keep refrigerated for 8 hours to marinade. Discard any remaining marinade.
Cajun Roasted Sweet Potatoes: Cut 1 pound of sweet potatoes into ½-inch x 2-inch strips. In a mixing bowl, toss sweet potatoes with olive oil. Arrange potatoes in a single layer on a baking sheet. Evenly sprinkle 1 teaspoon Cajun seasoning over sweet potatoes. Roast in a 400°F oven for 25 minutes or until tender.
Salsa: In a bowl, combine diced tomato, diced red onion, minced jalapeño, second-listed cilantro, second-listed lime juice and salt for salsa. Mix well. Keep refrigerated until ready to use.
Grill marinated chicken over medium heat 4 to 5 minutes per side or until cooked through, turning occasionally. Place grilled chicken breast on a plate. Garnish with 2 tablespoons fresh Salsa. Serve with Cajun Roasted Sweet Potatoes.