Place the garlic cloves on a cutting board. Slice the cloves in half lengthwise and then smash with the side of a chef's knife. Sprinkle the salt over the garlic and chop and smear the garlic against the cutting board until it makes a paste. (This can also be done using a mortar pestle; smash the garlic halves before placing them in the mortar.) Put the garlic paste in a small bowl and mix in 1 tablespoon of the olive oil.
Put the meat in a baking pan and prick it all over with a fork or metal skewer. Evenly rub the garlic paste on the meat. Marinate at room temperature for 1 hour.
Preheat the oven to 400 degrees F. Scrape as much of the garlic paste off the meat as possible so it does not burn in the oven.
Heat a large oven-safe skillet (preferably cast iron) over medium-high heat. Pour in 3 tablespoons of the olive oil and sear the beef until browned on both sides, 4 to 5 minutes total. Transfer the skillet to the oven and cook the roast for about 35 minutes for medium and up to 45 minutes for medium-well. (remember that the roast will continue to cook while resting outside of the oven, so it's best to remove the roast from the oven when it's slightly underdone). Check the color of the roast by making a small slit in the thickest part to check the color (remember that the meat on the edges of the roast will be more well done) or use a digital thermometer to check its temperature (128 to 129 degrees F for medium-rare). Remove the roast from the oven, cover with foil, and set aside to rest for 10 minutes before slicing.
While the roast rests, preheat a grill pan over medium-high heat. Alternately thread the cherry tomatoes and pearl onions onto wood or metal skewers. (If using an outdoor grill, soak the wooden skewers in water for 30 minutes to prevent them from burning.) Brush the tomatoes and onions with the remaining 1 tablespoon of olive oil and season with salt and pepper. Lay the vegetable skewers on the grill pan and char on both sides. Serve on a platter alongside the sliced beef.
*If you don't have an oven-safe skillet, you can transfer the roast fat side up to a roasting pan and follow the recipe instructions as described above.