Juice ¼ of the grapefruit into a small bowl, segment the rest. Set aside.
Separate the stalks and fronds from the fennel bulb. Thinly slice the stalks and roughly chop the fronds. Place in a large bowl. Cut fennel bulbs in half and thinly slice with a knife or mandoline.
Add the bulbs to the bowl with the fronds and stalks along with basil, mint, and grapefruit segments. Stir to combine, then add in the grapefruit juice and ¼ teaspoon salt, mix. Allow to sit for 5 minutes. Then, stir in the beans, ¼ teaspoon more salt, sambal, and ¼ cup oil. Serve immediately.
Photography and styling by Jenny Huang.