Recipe(tried): Savory Beef, Szechuan style

Try this. I think you are talking about this dish which I have modified to general tso's chicken for BG a white ago... (But the one you ate in the local restaurant may have their own modification as well.) See if you like it.
If not, tell me more about it and I see if I could be at help. (PS. I will be gone for 2 weeks from 19th, so my reply could be late.) (PPS It could be "Orange beef" as well, since there is not much veggies! Happy hunting!)
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Savory Beef
for 2-4 (depends on whether you serve it with other dishes.)

300g beef (use Scotch fillet/eye fillet/rump steak --rump steak can be tough)

Marinade:
1 T: each: soy sauce, cornstarch
1 egg yolk

4 T. topioca flour/cornstarch (or more)
enough oil for deep-frying

Mixed vegetables: total about 1 1/2 cup, uniformly sliced.
water chestnuts, gherkin cucumber, red capsicum, onion, carrot & etc.
(Your local restaurant didn't use much vegetables, just reduce this or omit it all together. BUT veggies are good for you!)
Aromatic:
2 t. each: ginger roots (grated or minced); garlic (minced)
2 t. hot bean paste (You can buy this in a jar in Asian grocers. Find the ones says Hunan or Szechuan.)

Sauce mix:
5 T. water (If you prefer it saucier, add more water when you cook the dish...)
1 1/2 soy sauce (If your hot bean sauce is salty enough, cut this down!)
1 t: each: sugar, vinegar (best use rice vinegar or black vinegar), topioca flour/ cornstarch

Tenderize the meat by striking it with a meat mallet or the dull edge of a knife (or Chinese cleaver.) Score the meat to help it better absorb the seasonings and to further tenderize it. Cut into chunks. Make sure the chunks are similar in size. Mix in the Marinade. Use your hand to "massage" the meat. You will find the sauce disappeared after a while.

Coat the meat pieces in topioca flour just before deep-frying. (Shake off the excess flour from the meat.)

Heat the oil for deep-frying. Fry the meat chunks over medium heat until lightly golden and surface is crispy. Remove from oil and drain well.

Heat 2T. oil until hot add the vegetables of your choice and quickly stir-fry them briefly. (If too dry, add a bit of water.) remove from the pan or push them to a side. Add the Aromatics right away and stir-fry briefly. Add in the Sauce, mix, and bring to a boil. Add the meat and mix together everything. Remove from heat.

Sever this with steamed rice.