How about something like this:
An overwhelmingly tall figure stood in the corner of the
room. Beside him, a skinny figure sat motionless on a chair. Suddenly, the
tall figure moved to the opposite side of the room and started
palpating the wall, the other then started crawling and
palpating the floor, both acting as if looking for something. The tall
figure then started laughing loudly and clapping his hands as if he
were overjoyed. His companion, on hearing this, started doing the
I didn't like the "tall figure was tall" construction in the first sentence, so lost one of the talls. The description of the skinny figure is also compressed.
I've used an adverb to emphasise a break between the initial description of the two figures and when they start moving. "Suddenly" might not be the right choice for what you have in mind.
I really didn't like "one did this as if looking for something, then the other did that as if looking for something." Way too repetitive. So I pull the "looking for something" bit into a separate sentence.
Although I've left it in my version, I'm not crazy about using "palpating" (especially twice!). It's a very technical term which doesn't properly apply to walls or floors. I'd consider looking for two suitable synonyms: "One started searching the wall, then the other started examining the floor." If you must, leave one figure palpating but choose a different verb for the other. I think, if you pick two more suitable verbs, you might not need to add the "as if looking for something" bit at all.
Is the tall figure a "him" or an "it"? You use both pronouns in your short passage: "The skinny figure right beside him sat on a chair. [...] The tall figure then started laughing loudly and clapping his hands as if it were overjoyed!" I've gone with "him" in my version.
I swapped "the skinny figure" for "his companion" in the final sentence to reduce the repetition. The only repeated phrases left are three "tall figure"s (which I think is OK), and two "palpating"s (which I don't like - see above).