Heat the olive oil in a large skillet over medium heat.
Drop in the garlic, pepper flakes, and a pinch of salt and stir frequently until the garlic turns golden and infuses the oil, about 2 to 4 minutes. Be careful not to let the garlic burn.
Add the broccolini to the skillet and cook, turning occasionally, for 2 to 3 minutes.
Pour in the water carefully--it will steam and may splatter--raise the heat to high, cover, and steam for 3 to 4 minutes.
Uncover the skillet and season with salt, if needed. Continue searing the broccolini until it's charred to your liking, 2 to 5 minutes.
Spritz some lemon juice over top and rush to the table.