In medium saucepan, place potatoes and enough water to cover by 1”. Add kosher salt. Bring to a boil and then reduce heat to maintain a slow boil. Cook potatoes until tender, 15-20 minutes, depending on size. Drain and reserve.
Make the mojo: Place cilantro, garlic, Serrano chile, lime juice, and kosher salt in food processor. Process until fairly smooth, but still with some texture. Add olive oil in a thin stream and mix thoroughly.
In medium bowl, toss cooked and cooled baby potatoes with about 3 tablespoons of mojo or more to your taste. Serve at room temperature.
Remaining Mojo can be stored in a glass jar in refrigerator for 2-3 days.