The Automation Guy
Known around here
If you have access to both sides of the concrete, then using water pressure to bore through the soil works really well. Obviously that won't work in this case since the sidewalk butts up to the house. The next easiest method is to cut a groove in the concrete deep and wide enough to place the wire in (but it doesn't have to go through the entire slab). Put the wire in the grove and use some caulk or concrete filler to cover it up. Depending on how much you have to cut, using a grinder with the right type of cutting wheel (for small jobs), or renting a concrete saw (for large jobs) are both good options.