Salsa: Combine the tomato, onion, jalapeno, and cilantro in a bowl. Mix well and season with salt and pepper, to taste. Set aside.
Preheat the oven to 350 degrees F.
Brush the chicken breast with olive oil and sprinkle generously with salt and pepper, to taste. Put the chicken on a small sheet pan and roast until fully cooked through, about 25 minutes. Remove the chicken from the oven and allow it to cool before shredding.
In a medium shallow skillet add the vegetable oil until it completely coats the bottom, heat the oil until it starts to shimmer. Scoop about 2 tablespoons down the center of each corn tortilla. Roll up each tortilla like a cigar and secure them with a toothpick. Fry the tacos until golden brown on all sides, turning once, about 4 minutes total. Remove the toothpicks and cut each taco in half.
To serve: Top with shredded lettuce and freshly made salsa. Drizzle with Mexican crema and sprinkle with crumbled queso fresco.