When standing on a wire, you can click on the tile beneath you to place a wire in the direction you're facing. (although, IIRC, clicking in a certain direction around your character will automatically change your facing, so I'd just click to the right of your character on the tile to make a wire in that direction.)
[@] (facing right) = [@-]
Unless I'm misunderstanding you, this should be the last resort. Any of the other options should be used first, unless you *want* to fritter away power with pointless knots everywhere.
And on the solars it's never necessary. Stand on the tile just beyond where the wire from the station ends, with a coil in hand. Click the knot at the end of that wire, then click that wire again (not the tile). Move one space further out. Repeat until you're even with the first set of panels. (If your cursor is aligned exactly right you can just click twice, move, click twice, move, etc. keeping the mouse stationary.) Click each of the knots and then each of the wires in turn (from the station and from the arrays), until they meet in a knot in the center. Now, go *back* one square. Carefully click the wires from the arrays, once each, on the tile you just came from. This will curve them. Now go out two tiles, to the next empty square. Repeat what you did at the beginning, with clicking the knot and clicking the wire, and moving out another square. Pretty much do this until you reach the tracker, stopping to link up each array.
Do this properly, and there will be only a single knot on the entire line, where you link up with the wire from the tracker. I think you can use wire cutters on that to remove it, but I usually don't bother.
Once you finish linking up the tracker and the arrays, go back, set the array to auto at the console, make sure the battery is configured properly, and then get the next one.
And yeah, it's probably best to set up the array next to engineering before trying to start the singularity. Otherwise you'll rarely have enough power.