What can I use to hang an object on ceramic tile?

It is common to drill through bathroom ceramic tile and its backing to install plastic anchors for screws for grab bars.

If there is a stud where you want to place the hook, then an anchor would not be absolutely needed, but you would need a long enough screw to reach 1 inch into the stud. However, you could drill a large enough diameter hole into the stud deep enough to receive the end a plastic anchor.

When drilling into a ceramic backslash in a kitchen you want to be careful not to hit electrical wires or plumbing. Be sure there is not a vertical plumbing vent where you want to drill, or water supply line, e.g., for a refrigerator ice maker or pasta pot faucet.

Even if you have no reason to suspect wires or pipes, and you proceed with drilling, drill just barely through into the space, then pull the drill out and probe through the hole with a wooden dowel or a screwdriver to make sure the space is open.

Alternatively, you could just glue to hook to the tile.

Easiest way is to use silicone caulking or like substance. Silicone will hold up 1.5 pounds quite easily and can be cleaned off ceramic tile completely. And can be cleaned off clock, yet it may stain the back.

Drill a 1" deep hole into a grout line (or at a corner between 4 tiles) and use a simple plastic anchor and screw hook.

For a 1.5lb wall clock ... You don't need a tile bit (use the grout line) You don't need a joist. You don't need to drill deep enough to hit any wires or pipes. You don't need to rely on command strips or glue. The tile cement and backing board will very nicely hold a simple plastic anchor. (Don't use a drywall anchor or anything fancy with ribs etc.).

If you want the clock in a very specific location that is not on a grout line, it gets just a bit more complicated. Buy a tile bit for your drill and use youtube to learn to use it. Not much to learn, just how to get it started without dancing or damaging the tile.

If you don't want a hole in the tile, get some hooks:

If they're adhesive, remove the adhesive on the back, and use some MS Polymer caulk like Bostik MS118 to stick it to the wall. This has excellent adhesion to tile.

If you use a hook that is designed to be mounted with a screw, make sure it looks like the one above, with the hook on the bottom. If the hook is on top, like these:

... then it will have a lot more leverage to pull the hook off the tile and unglue it.